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JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

VOLUME XLI • • • JULY, 1943

CONTENTS

PAGE
Motion Picture Standards in Wartime D. E. HYNDMAN 3

The Removal of Hypo and Silver Salts from Photographic
Materials as Affected by the Composition of the
Processing Solutions
J. I. CRABTREE, G. T. EATON, AND L. E. MUEHLER 9

Effect of High-Intensity Arcs upon 35-Mm Film Projec-
tion

E. K. CARVER, R. H. TALBOT, AND H. A. LOOMIS 69

Film Distortions and Their Effect upon Projection Quality

E. K. CARVER, R. H. TALBOT, AND H. A. LOOMIS 88

Carbon Arc Projection of 16-Mm Film W. C. KALB 94

The Practical Side of Direct 16-Mm Laboratory Work

L. THOMPSON 101

Society Announcements 119

(The Society is not responsible for statements of authors.)

JOURNAL OF THE SOCIETY OF
MOTION. PICTURE ENGINEERS

SYLVAN HARRIS, EDITOR
ARTHUR C. DOWNES, Chairman

Board of Editors

JOHN I. CRABTREE ALFRED N. GOLDSMITH EDWARD W. KELLOGG
CLYDE R. KEITH ALAN M. GUNDELFINGER CHARLES W. HANDLEY

ARTHUR C. HARDY
Officers of the Society
** President: HERBERT GRIFFIN,

90 Gold Street, New York, N. Y.
** Past-President: EMERY HUSB,

6706 Santa Monica Blvd., Hollywood, Calif.
** Executive Vice-President: LOREN L. RYDER,
5451 Marathon Street, Hollywood, Calif.
*Engineering Vice-President: DONALD E. HYNDMAN,

350 Madison Avenue, New York, N. Y.
** Editorial Vice-President: ARTHUR C. DOWNES,

Box 6087, Cleveland, Ohio.
* Financial Vice-President: ARTHUR S. DICKINSON,

28 W. 44th Street, New York, N. Y.
** Convention Vice-President: WILLIAM C. KUNZMANN,

Box 6087, Cleveland, Ohio.
^Secretary: E. ALLAN WILLIFORD,

30 E. 42nd Street, New York, N. Y.
^Treasurer: M. R. BOYER,

350 Fifth Ave., New York, N. Y.
Governors

*H. D. BRADBURY, 411 Fifth Avenue, New York, N. Y.
*FRANK E. CARLSON, Nela Park, Cleveland, Ohio.
*ALFRED N. GOLDSMITH, 580 Fifth Avenue, New York, N. Y.
*A. M. GUNDELFINGER, 2800 S. Olive St., Burbank, Calif.
*CHARLES W. HANDLEY, 1960 W. 84th Street, Los Angeles, Calif
*EDWARD M. HONAN, 6601 Romaine Street, Hollywood, Calif.
*JOHN A. MAURER, 117 E. 24th Street, New York, N. Y.
**WILLIAM A. MUELLER, Burbank, Calif.

*HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood, Calif.
**H. W. REMERSHIED, 716 N. La Brea St., Hollywood, Calif.
"JOSEPH H. SPRAY, 1277 E. 14th Street, Brooklyn, N. Y.
**REEVE O. STROCK, 195 Broadway, New York, N. Y.

*Term expires December 31, 1943.
**Term expires December 31, 1944.

Subscription to non-members, $8.00 per annum; to members, $5.00 per annum, included
in their annual membership dues; single copies, $1.00. A discount on subscription or single
copies of 15 per cent is allowed to accredited agencies. Order from the Society of Motion
Picture Engineers, Inc., 20th and Northampton Sts., Easton, Pa., or Hotel Pennsylvania, New
York, N. Y.

Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.

Publication Office, 20th & Northampton Sts., Easton, Pa.

General and Editorial Office, Hotel Pennsylvania, New York, N. Y.

Entered as second-class matter January 15, 1930, at the Post Office at Easton,

Pa., under the Act of March 3, 1879. Copyrighted, 1943, by the Society of Motiou

Picture Engineers, Inc.

MOTION PICTURE STANDARDS IN WARTIME*
DONALD E. HYNDMAN**

An American bomber is zooming its way to enemy territory on an
important mission of destruction. It reaches the outskirts of its
destination, loses altitude, the bomb-bay doors are opened. The
bombardier sights his target, the bombs are released. The photog-
rapher aims his motion picture camera as the bombs fall and presses
the release lever — it starts — groans and stops — dead. The bomber
returns to base with no photographic record to show whether a "hit"
or a "miss" was made. Why did the camera fail? Was the diameter
of the sprockets too great or too small? Was the film perforated
under- or over-pitch for the sprockets? Was the film core binding
on the spindle because it was too wide? Was the failure caused by
non-interchangeability of parts and materials?

Of course, such an incident did not occur because standards were
employed in manufacturing the camera, accessories, and film.
Standards avoid such dangers. Standards provide interchange-
ability, simplification of groups of articles, economies in manufacture,
agreement between purchaser and purveyor on specifications, and
avoid entanglements and misunderstandings.

To avoid misconception and to acquaint the uninitiated, it seems
best that definitions of the terms and concise descriptions of the
methods employed in standardization procedure be given as an in-
troduction to Motion Picture Standards. The following definition
of an SMPE Recommended Practice has been approved by the
Board of Governors and the Standards Committee of the Society of
Motion Picture Engineers. The following definition of an American
Standard has been approved by the executive-secretary of the
American Standards Association.

SMPE Recommended Practice. — An SMPE Recommended Practice is a de-
scription of a recommended process, method, construction, or device intended to
accomplish a specific and desired aim. This issuance of such a Recommended

* Presented at the 1943 Spring Meeting at New York, N. Y.
** Engineering Vice-President of the Society.

4 D. E. HYNDMAN [j. s. M. P. E.

Practice indicates that it is acceptable to the Standards Committee and to the
Board of Governors of the Society of Motion Picture Engineers. Its publication
by the SMPE constitutes a recommendation to interested parties that it be
utilized as a habitual procedure, an\i that comments or criticisms concerning its
effectiveness in practice are welcomed and will be considered.

American Standard. — American Standard is a form of approval given by the
American Standards Association to specifications, safety codes, methods of test,
definitions, abbreviations, and the like. Its adoption and publication by the
authorization of the American Standards Association recommend to interested
parties that it be accepted as a standard in industry, commerce, and elsewhere
because it is believed to be technically, scientifically, and industrially effective
and acceptable. An American Standard, having been approved according to a
prescribed democratic procedure by a nationally recognized body of technical
and scientific experts or specialists drawn from engineering organizations, in-
dustry, the government, consumers, and other legitimately interested groups, will
normally receive full approval and acceptance in practice by a wide group of users.

Under the heading of Specifications would be included tables of dimensions
with tolerances necessary to insure interchangeability in quantity production as
well as requirements of a chemical, physical, or metallurgical nature necessary to
insure a quality. Specifications, of course, may also include a definite and
specific method of test.

The general standardization procedure is based upon the demo-
cratic method that a proposal, to become an SMPE Recommended
Practice or American Standard, may be originated or proposed either
singly or collectively by any interested person, group, commercial
organization, or scientific, technical, or engineering society, etc.

A proposal when submitted to the SMPE is referred to the Stand-
ards Committee. This committee is composed of authoritative en-
gineers and technicians of the motion picture industry, representing
producers, distributors, exhibitors, and manufacturers of all types of
equipment utilized in the industry. The Committee follows a very
specific procedure prescribed by the Administrative Practices of the
Society. The Committee carefully studies the proposal, prepares
the necessary forms, and requests written comment from interested
parties before deciding whether the proposal should be classified for
consideration as an SMPE Recommended Practice or for submission
to the American Standards Association recommending its considera-
tion for an American Standard.

Following approval of the proposal by the Standards Committee,
it is submitted to the Board of Governors and, if approved, is pub-
lished in the JOURNAL with an announcement of its validation as an
SMPE Recommended Practice.

It is unlikely, however, that a proposal would not first become an

July, 1943] MOTION PICTURE STANDARDS IN WARTIME 5

SMPE Recommended Practice before being considered for or be-
coming an American Standard because as an SMPE Recommended
Practice it constitutes a recommendation to interested parties that
it be utilized as a habitual procedure and that comments or criticisms
concerning its effectiveness in practice are welcome and will be con-
sidered. This procedure gives all interested parties ample time to
try thoroughly the recommendation before it is advanced to the
higher status of a standard.

When a proposal, whether it be merely a new project or an SMPE
Recommended Practice, is submitted to the ASA for consideration
as an American Standard, it is referred to the Sectional Committee
on Motion Pictures, Z-22. This Sectional Committee, composed of
representative technical and engineering authorities from the motion
picture industry, representing producers, distributors, exhibitors,
and manufacturers of all types of motion picture equipment, care-
fully studies the proposal, arranges the form, and requests comments
from all interested parties. If the project is approved, the Sec-
tional Committee forwards its recommendation to the parent body,
the American Standards Association. The ASA now studies the
recommendation of the Sectional Committee and, if approved, an
American Standard is issued with announcement of validation by
the "supreme court" of American standardization.

Obviously many important details are left out of this description of
the standardization procedure, but space permits mention of only
the important features of the process. An important point is that
there are no SMPE Standards. Only SMPE Recommended Practices
exist; and only the ASA has the right to validate American Stand-
ards. There have been no American Recommended Practices
since February, 1943.

Few persons realize the value of standardization procedures.
They may do so subconsciously in their daily lives and tasks but
they do not realize that the food they eat, the clothes they wear, the
cosmetics, detergents, and the luxuries they buy, as well as the tools
necessary to process and fabricate practically all the materials and
products, are the results of the work of technicians and engineers
who have spent many days, weeks, and months on the problems of
standardizing both the articles manufactured and the processes of
manufacturing them so as to assure consistent-quality mass-produc-
tion of the things that contribute to better living. Standardization
speeds up production, refines individual and collective quality control,

6 D. E. HYNDMAN [J. S. M. p. E.

maintains a consistent level and dispersion of quality and quantity,
provides means for rapid inspection and sampling, produces normal
distribution of quality and quantity, and brings to the consumer a
uniform product. In addition, it promotes interchangeability of
specific products serving the same purpose, allowing the consumer
to choose products on the basis of quality, service, and utility. It
thus constitutes an economic saving and a major convenience to
producer and consumer alike.

In current circumstances we apply peacetime knowledge to wartime
practice; and when this war is over, both peacetime and wartime
knowledge will be applied to postwar practice. The last war
necessitated standardization to increase production, to husband the
use of scarce materials, to .create new uses for available substitutes,
and to develop new materials and new processes. These develop-
ments did much to provide better living conditions and to bring
greater happiness to the people of the world in the quarter-century
prior to the starting of this war. Unfortunately, alien and destruc-
tive forces partly annulled these gains. In the developments follow-
ing the present world conflict probably even greater improvements
will take place because the speed of production and efficiency of de-
struction in this war "has proceeded at a much greater rate, demanding
more materials and more accurate machinery of war. This demand
has forced a rapid development of new materials as substitutes for
scarce materials. Sometimes the substitutes prove better in many
ways than the original material. The same will be true in the
"postwar" period.

Since Pearl Harbor, "War Model Standards" have been evolved
and put into commercial practice in many fields of endeavor. This
has been rapidly accomplished through the cooperation of industry,
government agencies, such as the War Production Board, Office of
Price Administration, etc., the technical and engineering societies,
and the American Standards Association. This cooperation has
resulted in radical reductions in the thousands of items produced
in some fields. It has also, in many instances, brought about
simplification of models, utilization of substitute materials, and
increased production of fewer items. The effort has netted great
savings of scarce materials for more important purposes, and has
efficiently conserved both essential and non-vital goods.

In the electrical field, from approximately several hundred types
of electronic tubes, capacitors, volume controls, power transformers,
chokes, transformers, etc., the new "War Model Standards" have

July, 1943] MOTION PICTURE STANDARDS IN WARTIME 7

reduced the number of types to approximately one to twenty-five,
depending upon how readily interchangeability can be effected.
The performance and design standards provide for using a minimum
of strategic materials, but being satisfactory from an electrical and
service life standpoint to avoid, if possible, replacing replacement
parts. New specifications for insulators and insulating pieces cover
performance characteristics, preferred shapes, and interchange-
ability for various types of ceramic materials to assure the avail-
ability of needed parts. Such standards are of vital interest to the
motion picture industry as they apply to electrical equipment,
sound recording and reproducing equipment, sound projectors,
power supplies for studio lighting and theaters, general wiring, etc.

Many substitutes for strategic materials have been evolved. In
many types of electrical wiring installations copper wire is covered
with synthetic plastic material which serves as insulation in place
of rubber. A mixture of plastic and cotton cord provides material
to fabricate liquid-carrying hose in place of the rubber and cord hose
formerly used. A number of motion picture laboratories are using
synthetic plastic tubing to replace flexible rubber hose or hard-rubber
pipe for carrying photographic solutions to and from continuous
developing machines. This plastic tubing can be obtained in a wide
variety of wall thicknesses and diameters, and it can not only be bent
at any angle, avoiding the use of elbows, but can also be threaded
for joints when desired, like all hard-rubber and metal pipe. Plastic
sheets, tubes, and rods are now finding utility where before it was
believed only stainless steel or rubber could be safely used.

Such developments are the results of standardization in wartime.
It must always be the object to effect interchangeability of parts and
materials, to utilize substitutes for strategic materials whenever
possible, to minimize the number of items of any one type, to specify
preferred shapes, to maintain performance and life characteristics
comparable to or better than those of the original items, and to mini-
mize replacements.

There are fields waiting for further enrichment. Much can be
done to standardize the equipment and procedures of motion picture
production, distribution, and exhibition. Improvements can be
made, with proper specification of new materials and processes, that
will produce more goods at lower cost. For instance, there is evi-
dence that continuous developing machines and printers can be
sufficiently improved in design to increase the footage output per
man-hour two to four-fold, and obtain a quality of product equivalent

8 D. E. HYNDMAN

to, or even better than, current products. Accessory equipment
like manual and semi-automatic rewinds, hand and machine splicing
equipment, cutting and editing equipment, requires more efficient
design. A study of the tooth shapes and diameters of all types of feed,
holdback, and intermittent sprockets is essential to increasing the use-
ful life of motion picture film. This future development demands and
warrants the attention of the most competent engineers in the in-
dustry. Realization of these goals would materially increase produc-
tion, decrease production costs, and produce an even better product.

As a note of caution, individualistic industry might misinterpret
the purposes of standardization. Standardization does not mean
that improvements are barred or limited; on the contrary, it does
mean that only the best is used. Only proved recommended changes
become formal standards. Individual capable management is still
the secret of producing high-quality products. Nothing is taken
from individual effort and ability; but, rather, individual effort
and ability are given better tools with which to produce even better
individualistic products. Standardization properly applied assures
present stabilization with enterprise for the future.

The motion picture industry faces not only many problems that
are common to other industries but it has also specific problems unto
itself. The conservation of motion picture film attended with the
conservation of all types of materials that are normally utilized in
the production, distribution, and exhibition of motion pictures,
necessitates that each and every one connected with the industry
shall realize that full cooperation is essential for maintaining the high
standards of entertainment expected by the public. The problems
are upon us. It is in this spirit that the technical committees of the
Society, on Cinematography, Color, Exchange Practice, Laboratory
Practice, Non-Theatrical Equipment, Preservation of Fiim, Process
Photography, Sound, Standards, Studio Lighting, Television,
Theater Engineering, Projection Practice, Theater Design, Screen
Brightness, and Theater Protection continue studying the pro-
cedures in their respective fields to assist the motion picture industry
in solving the technical conservation and procedure problems as they
arise. Much work has been done and published by these Com-
mittees on recommendations for Conservation of Film, Projector
and Projection Room Design, Theater Design, and Theater Pro-
tection, Investigation and study are now in progress. Suggestions
will be welcomed by these Committees and the Officers of the Society.

THE REMOVAL OF HYPO AND SILVER SALTS FROM

PHOTOGRAPHIC MATERIALS AS AFFECTED BY

THE COMPOSITION OF THE PROCESSING

SOLUTIONS*

J. I. CRABTREE, G. T. EATON, AND L. E. MUEHLER**

Summary. — During processing, if photographic materials are insufficiently fixed
and washed, the silver thiosulfates and sodium thiosulfate retained may result in
staining of the non-image areas and fading of the image during subsequent storage.
In the case of films and plates the thiosulfates may be removed completely if a judicious
choice of hardening and fixing baths is made and if the most effective washing tech-
nique is employed but, with prints, traces of hypo are invariably retained which can
be removed by subsequent treatment in a peroxide-ammonia solution.

Several factors contribute to the retention of sodium and silver thiosulfates and the
extent of this retention was measured by careful determination of the residual thio-
sulfate and silver in the processed material. The hardening agent, potassium alum,
used in hardening baths and fixing baths caused the greatest retention while chrome
alum had little effect. The accumulation of silver during exhaustion of the fixing bath
resulted in retention of silver thiosulfates.

The removal of sodium and silver thiosulfates was aided by (1) use of a second fixing
bath to remove silver and (if non-hardening) to assist removal of hypo, (2) an increase
in the pH of the fixing bath preferably above the isoelectric point of gelatin, (3) harden-
ing prior to fixation as compared to hardening during or after fixation, (4) raising the
temperature of the wash water, (5) increasing the pH of the wash water or by the
use of a dilute ammonia solution near the end of the washing process. These treat-
ments were less effective with photographic papers because of the high retention of
thiosulfates by the paper base and the baryta coating. Processing recommendations
to insure permanency during (a) archival and (b) normal periods of storage are
given.

INTRODUCTION

When a photographic film or paper is insufficiently washed during
processing, hypo together with silver thiosulfates is retained and,
if the concentration is sufficiently great and the conditions of storage
are appropriate, fading of the image results. In the case of film with

* Presented at the 1942 Fall Meeting at New York; received January 8, 1942.
Communication No. 862 from the Kodak Research Laboratories.
** Eastman Kodak Company, Rochester, N. Y.

CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

nitrocellulose base, when exposed to high temperatures, nitrogen
oxides may be liberated1 and, in the presence of moisture, the re-
sulting nitric acid reacts with the silver image causing fading.

In this paper the term "fading" refers to any change in the density
or hue of the silver image which may or may not be accompanied
by a staining in the highlights. The chief causes are: (a) sulfiding
of the silver image by the sulfur present in the residual hypo,2 and/or
(b) the decomposition of residual sodium silver thiosulfate complexes
which produces sulfiding of the image together with silver sulfide
in the highlights.

The process of fixation consists in the conversion of the insoluble
silver halides (chloride, bromide, or iodide) in the emulsion to soluble
complex silver thiosulfates and the process of washing consists
in the removal in solution of sodium thiosulfate together with a
small proportion of silver thiosulfates.

The ultimate result of incom-
plete fixation and/or incomplete
washing is the conversion of the
silver present in the residual sil-
ver thiosulfate to silver sulfide
by virtue of decomposition of
the silver thiosulfate, or by re-
action with hydrogen sulfide
present in the atmosphere. The
results of these reactions are
visible in the dense area of a film or print by reflected light as either
a yellowish stain or a metallic luster and in the highlights as a
yellowish to yellowish brown stain of silver sulfide.

In any consideration of washing, therefore, it is important to
ascertain the concentration of both the residual silver ion and thio-
sulfate ion and to study the changes in the proportion of the two as
washing progresses.

Most of the experiments outlined below were made with motion
picture films but in general the results obtained apply also to other
photographic films.

In order to determine the relative sensitivity of motion picture
images to residual hypo, strips of various processed motion picture
negative, positive, and sound-recording emulsions on safety type
base, containing known quantities of hypo, were placed in a sealed
glass vessel which contained water, and stored for several days in an

FIG. l.

Experimental washing appa-
ratus.

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 11

oven maintained at a temperature of 110°F. The strips were sus-
pended on glass rods supported by glass frames and the condition
of the film noted at definite intervals. These storage tests assisted
in the determination of certain maximum permissible hypo con-
centrations (sodium thiosulfate crystal, Na2S2O3-5H2O) with respect
to fading for various types of materials. These maximum tolerable
quantities were tentatively set at 0.05 milligram per square inch for
coarse-grain negative, 0.01 milligram per square-inch for positive
or fine-grain positive, and 0.005 milligram per square-inch for ex-
tremely fine-grain negative and positive films such as Microfile.
With concentrations of residual hypo greater than these, indications
of fading, especially in the halftones, were obtained under the ex-
treme storage conditions used.

The relationship between accelerated fading tests and normal
storage conditions has not been precisely determined. However,
negative and positive motion picture films which have been stored
at Kodak Park3 for at least ten years at 55°F and 70 per cent relative
humidity and which contained quantities of hypo of the order of
that in present-day commercially processed emulsions have not
shown signs of visible fading. A period of one day in the accelerated
test would therefore appear to be equivalent to a period of not less
than ten years at a temperature of 55°F and 70 per cent relative
humidity. For shorter times of keeping greater quantities of hypo
than those stipulated may be tolerated.

In this connection it is of interest to know the approximate hypo
and silver contents of some films and papers processed commercially.
Many samples of films and prints from various sources have been
tested during the past few years for hypo and silver content and the
results shown in Table I indicate the existence of a wide variation
in hypo content. In general the residual silver content was very
low.

With the present trend toward the use of fine-grain emulsions for
sound recording and projection print purposes, and the increasing
use of fine-grain Microfile film for archival storage, it is of increasing
importance that the hypo be removed from films as completely as
possible during processing.

To date, although laboratory technicians have realized the im-
portance of thorough washing it has been generally considered that
the most important factors which influence the removal of silver
and thiosulfate compounds are (a) time of washing, and (b) rate

12 CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

of renewal of the water. The effect of the nature of the processing
solutions has been given little consideration.

TABLE I

Average Hypo and Silver Contents of Some Commercially Processed Negatives and

Prints

Film Hypo (Mg per Sq-In) Silver

Motion picture negative Nil ->0.18 Nil —*- Trace

Motion picture positive Nil -*• 0.18 Nil — »• Trace

Photofinishers

(a) Machine processed 0.35 — »• 0.50* About 0.01 mg per sq-in

(b) Hand processed 0. 10-* 0.15* Nil
*-ray 0.35 -* 0.50* Trace

Paper

Single weight

(a) Machine processed 0.15-»-0.35 Trace

(6) Hand processed 0. 10-* 0.20 Trace

Double weight 0 . 25 -»• 0 . 45 Trace-0 . 01 mg per sq-in

* These films are coated on both sides and the data represent the concentrations
of hypo in only one of the coatings. When the hypo content was determined by
the mercuric chloride test, the total hypo content was measured and was, in each
case, twice the value given.

Data in the literature regarding the effect of the composition of
the processing baths on hypo removal are sparse and generally in-
conclusive. As early as 1900 Gaedicke4 stated that alum-hardened
plates required excessive washing compared with non-hardened
plates. In 1917 Liippo-Cramer,5 commenting on Elsden's6 use of
neutral thiosulfate, reported that a highly acid non-hardening fixing
bath washed out more slowly than plain thiosulfate. Hickman
and Spencer7 in 1924 attempted to show the effect of hardening agents
and modified fixing baths on the washing of plates. They in-
vestigated the use of alum and formaldehyde between the developer
and fixing bath and the use of alum in the fixing bath. Formaldehyde
had no effect on the time of washing, while immersion in a 5 per
cent alum bath with adequate washing before and after "profoundly
influenced the retention of electrolyte." When alum was used in a
fixing bath maintained sufficiently acid to prevent subsequent hy-
drolysis, there was no difficulty in removing hypo or other electrolyte.
In view of this apparent uncertain effect of alums on washing, it
was considered desirable to make an extensive investigation involving
various types of present-day processing solutions in order to deter

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 13

mine the effect on hypo and silver removal of the use of various
developers, stop baths, fixing baths, and supplementary treatments,
and especially the effect of the presence of hardeners in the fixing
bath, variations in the pH of the bath, the time of fixation, and
the effectiveness of the subsequent washing procedure.

METHOD

At the outset it was realized that careful control of the various
factors involved would not be obtained by the use of trays or large
tanks, but a series of flat spiral reel outfits in use for the daylight
processing of 35-mm films proved satisfactory and permitted adequate
reproducibility of results.

One-foot lengths of the film were developed in 500 cc of the recom-
mended developer, drained for 10 seconds, rinsed 10 seconds in run-
ning water, hardened and fixed for four times the apparent "time
to clear" (see p. 25) in a 500-cc volume of the bath, drained 10
seconds, and finally washed in an experimental washing apparatus
designed to give a very rapid change of water and a high degree of
agitation as shown in Fig. 1. All the processing solutions and the
wash water were maintained at a temperature of 68°F and uniform
agitation was used throughout.

The water, which overflowed at B, was introduced through A
into the 2-liter circular tank C at a controlled flow such that the
outflow was 55 times the capacity of the vessel each hour. The
agitation produced by the water influx was increased greatly by the
use of a high-speed electric stirrer D having a slightly fluted convex
disk for the stirring propeller. Samples of the processed film were
mounted on a wooden rack E held in position in the tank. These
conditions were such that high-speed negative films fixed in fresh
baths, washed completely in 40 minutes following the most in-
hibitive treatment with respect to the removal of hypo. With
positive films the flow was reduced to 12 gallons per hour or about
two-fifths that used for negative film.

The majority of the tests were made with Eastman Motion Picture
Super- J£Jf Panchromatic Negative Film, Type 1232, but tests were
also made with the following Eastman Motion Picture Films:

Plus-Z Panchromatic Negative Film, Type 1231.
Background Panchromatic Negative Film, Type 1213.
Fine-Grain Panchromatic Duplicating Negative Film, Type 1203.
Release Positive Film, Type 1301.

14 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

High Contrast Positive Film, Type 1363.
Fine-Grain Duplicating Positive Film, Type 1365.
Sound Recording Film, Type 1357.

In addition, tests were made with Microfile, Type 5204, and paper
prints.

Melting-point determinations were made on each sample of
processed film to determine whether or not the degree of hardening
was seriously affected by modifications of the fixing and hardening
bath formulas.

The quantity of hypo retained by all the processed film samples
was determined by the mercuric chloride-potassium bromide method
of Crabtree and Ross8 in which one square-inch of film is placed
in a 10-cc volume of the reagent* and the resultant turbidity com-
pared with a series of standard turbidities. The latter are produced
by the addition of measured volumes of a 1:10,000 solution of hypo
to the 10-cc volume of the reagent.

Note: The fact that the total residual hypo in a film sample is
accurately measured by the mercuric chloride reagent has been
verified by two confirmatory tests: (1) when the film was washed
just enough to give a negative test with mercuric chloride, a negative
test was obtained with an excess of 1 per cent acidified silver nitrate
solution which reacts with all the hypo in situ, and (2) when one-
half of a film sample was soaked in water to equilibrium and the
solution tested with mercuric chloride, an identical value was ob-
tained as by direct determination on the other half of the film sample.

The quantity of hypo retained by prints was determined by
bathing the print sample in a 1 per cent (acidified) silver nitrate
solution, reacting the excess silver nitrate with sodium chloride,
fixing out the silver chloride with hypo solution, and then determin-
ing the transmission density of the silver sulfide stain. The cor-
responding quantity of hypo was read from a standard curve.

The relative quantities of silver retained by the processed film
samples were determined by the sodium sulfide spot test in which a
drop of 0.2 per cent sodium sulfide solution containing 1 cc of 40
per cent formalin per 100 cc was placed on the film for 5 minutes
and then removed with absorbent paper. The relative quantities
were recorded as density readings (D = log l/T) obtained by measur-
ing the percentage transmission of tungsten light through the silver

* For formula, see appended table of formulas.

July, 1943]

REMOVAL OF HYPO AND SILVER SALTS

Crabtree-Ros;

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Constituents

Sodium thiosulfate
Sodium sulfite (desi
Sodium bisulfite

*« »£, 'S £

Hi ; i 11

3 S ^ % | | S

8 •§ § 3 .g g •§ a

•^^2-d^«^8^rS
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Borax
Citric acid
Potassium metabisi
Mercuric chloride
pH value

Q
*

16 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

sulfide spot when the transmitted light was picked up by a photo-
electric cell, the output current of which was amplified and indicated
on a microammeter.

The pH of solutions was determined with the Beckman Industrial
pH meter standardizing with an acid phthalate buffer solution at
£H = 3.97.

The relative quantities of silver in prints were determined by spot
testing the emulsion side with 0.2 per cent sodium sulfide solution
and visually judging the intensities of the silver sulfide stains.

A further check was made on the relative silver contents by
subjecting samples of the prints to accelerated fading conditions
(over water at 110°F) which caused the silver thiosulfate complexes
to decompose to produce a silver sulfide stain.

The concentration of silver in fixing baths was determined by
using the Argentometer described by Weyerts and Hickman.9

The relative rates of hypo and silver removal were determined
for chrome alum (Kodak F-23), potassium alum (Kodak F-25 or
Kodak F-5), and non-hardening (Kodak F-24) fixing baths, and the
effect of increasing £H in each case was studied. Two-bath combin-
ations of these three types and modifications of them were also
investigated.

The effect of a series of wetting agents upon the removal of both
hypo and silver was also studied. The tests indicated that the
use of wetting agents had no practical value in this connection.

EFFECT OF COMPOSITION OF PROCESSING BATH

(1) Composition of the Developer.— Tests made under the
same conditions of rinsing, fixing, and washing with Kodak D-76, DK-
60a, D-72 (1:2), and D-7 (pyro) developers showed that there were
no differences in the rate of removal of hypo or silver from Super-
XX Panchromatic Negative Film, Type 1232, when using the
Kodak F-5 fixing bath.

(2) Composition of Stop Baths. — Although acid stop baths are
not invariably used when processing negative or positive films, a
comparison between water, a 2 per cent solution of acetic acid, and
a 3 per cent solution of chrome alum (Kodak SB -3) showed that
none of these baths had any appreciable effect in retarding or hasten-
ing washing when the Kodak F-5 fixing bath was employed.

(3) Composition of Fixing Baths. — Experiments by the authors
with paper prints and roll films have shown that the use of a fresh

July, 1943]

REMOVAL OF HYPO AND SILVER SALTS

chrome alum fixing bath10 causes an increase in the rate of hypo
removal as compared with the use of a fresh potassium alum fixing
bath. This was clearly demonstrated when Plus-X Panchromatic
Negative Film, Type 1231, was washed for 10 minutes in a vertical
glass tube with different quantities of water flowing through the
tube per unit of time. The quantity of residual hypo was plotted
against the rate of flow as shown in Fig. 2, from which it is apparent
that the rate of removal from chrome alum hardened film far exceeds
that from potassium alum hardened film.

With a chrome alum fixing bath apparently the hypo is not so
strongly held as in the case of potassium alum baths and is very

30 60 100

180 225

GALLONS PER HOUR

FIG. 2. Effect of rate of flow on rate of removal of hypo from
A : film fixed in fresh potassium alum fixing bath (Kodak F-25) \
B: fresh chrome alum fixing bath (Kodak F-23). Eastman
Plus-Jf Panchromatic Negative Film, Type 1231. Time of wash-
ing, 10 minutes.

readily washed from the film. The relatively thick Eastman Motion
Picture Films, Types 1231 and 1232, when washed under the ex-
treme conditions of 5 minutes in the experimental apparatus (Fig. 1)
at 41 °F, following the chrome alum fixing bath, retained only very
small quantities of hypo.

The use of a non-hardening fixing bath (Kodak F-24) without
pre- or supplementary hardening was slightly more effective than
the use of a chrome alum fixing bath with respect to hypo removal
but was impractical because of swelling of the emulsion and the
tendency for reticulation. A non-hardening fixing bath is practical
only when used in combination with a suitable hardening bath or
with films which are sufficiently hardened in manufacture

The variations in concentration of hypo in the fixing baths studied
had no effect on the rate of removal of hypo from processed film.

18 CRABTREE, EATON, AND MUEHLER [J. s. M. p. E.

Other ingredients (exclusive of alums) had no effect provided they
did not change the pH of the bath.

Under the experimental conditions described on p. 13, the silver
content of the washed film was essentially zero.

(4) pH of Fixing Baths.— The pH value of a fixing bath is signifi-
cantly related to its composition which results from a consideration
of sulfurization life, hardening properties, rate of fixation, exhaustion
life, and sludging properties.10-11 Various fixing bath formulas
therefore give different initial pH values as, for example,

Kodak F-23 — pH. = 3 . 1 — Chrome Alum
Kodak F-5 — pH = 4 . 1 — Potassium Alum-Boric Acid
Kodak F-10 — pU. = 4 . 6 — Potassium Alum-Boric Acid
Kodak F-6 — pU = 4 . 9 — Potassium Alum-Boric Acid

These baths were compared to determine whether or not a differ-
ence in initial pH affects the rate of elimination of hypo from film.
It is considered that the slight differences in the chemical constituents
of the potassium alum baths were unimportant as compared with
the £H differences.

TABLE II

Effect ofpH of Fixing Baths on Rate of Removal of Hypo (Eastman Super -XX 1232}

Time of Hypo Content (Mg per Sq-In)

Washing F-5 F-10 F-6 F-23

(Min) pH = 4.1 pH = 4.6 pH = 4.9 pH •» 3.1

10 0.20 0.12 0.02 0.02

25 0.08 0.06 Nil Nil

The data show that with potassium alum baths the rate of removal
of hypo is greatest with baths having a high pH value. It was also
found that by adjusting the initial pH of a fixing bath to a higher or
lower value by the addition of alkali or acid, a corresponding change
in the rate of removal of hypo resulted, but this procedure may
impair the optimum properties of the fixing bath. Although chrome
alum baths have low initial pH values there is no appreciable re-
tention of hypo after washing.

(5) Degree of Exhaustion of Fixing Bath: (a) Effect of pH
Change on Hypo Removal. — The F-23 chrome alum, F-5, F-6, and
F-10 potassium alum fixing baths were exhausted to approximately
500 feet per gallon with Eastman Super-JY^ Panchromatic Nega-
tive Film, Type 1232, and the pH, degree of hardening, and rate
of removal of hypo determined at different stages of the exhaustion.

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 19

The film was developed in D-76, rinsed 5 seconds in running water,
fixed for 20 minutes, and washed for 10 and 25 minutes in the ex-
perimental washing device shown in Fig. 1. In order to maintain
constant the quantity of fixing bath lost by carry-over when the
film samples were transferred to the washing apparatus, the films
were first suspended until the residual fixing bath began to drain
drop wise.

It was found that the slight increase in pH (approximately 0.5
unit) of the F-5 fixing bath during exhaustion under these conditions
was not sufficient to effect any appreciable change in the rate of
removal of hypo. However, when the ^>H of F-6 or F-10 was in-
creased by 0.5 unit, the hypo contents of the films decreased as
shown below:

Time of

Washing F-10 F-10 F-6 F-6

(Min) 0H-4.6 0H-5.1 0H-4.9 . PH.-5A

10 0.12 0.02 0.02 Nil

25 0.06 Nil Nil Nil

The £H of the F-23 chrome alum bath increased by 3 units. Removal
was very rapid after fixation in chrome alum baths at the £H of
the fresh solution and more rapid at higher pH values. It should
be remembered that with chrome alum baths the initial hardening
and non-sludging properties are retained for not more than 24
hours.10

If no rinse was used between development and fixation with
F-5, the pH increased more rapidly and effected somewhat greater

TABLE in

Effect of Exhaustion of Fixing Baths on Rate of Removal of Hypo

Comparison of "Rinse" and "No Rinse" Between Development and Fixation

Eastman Super -XX Panchromatic Negative Film, Type 1232

Hypo Content
(Mg per Sq-In)
Wash, Wash,

Bath pH 10 Min 20 Min

F-5, fresh unused 4.1 0 . 18 >0 . 04

F-5, exhausted to 400 ft per gallon with

rinse 4.60 0.14 0.34

F-5, exhausted to 400 ft per gallon, no rinse 5.45 <0.005 <0.005
F-5, exhausted to 400 ft per gallon with

rinse, pH adjusted 4.1 0.18 0.04

F-5, exhausted to 400 ft per gallon, no

rinse, pH adjusted 4.1 0.18 0 . 04

CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

changes in the rate of removal of hypo as shown in Table III. These
pH effects were further verified when the pH of the exhausted baths
was adjusted to the />H value of the fresh bath.

(b) Effect of Silver Content on Removal of Silver and Hypo. — As
mentioned previously, the concentration of silver in the clear portions
of the film is almost as important with respect to permanence as
the residual hypo in the film. As is the case with hypo, if the storage

0.14

FRESH

AGO

EXHAUSTION (FEET 35 mm. FILM PER GAL.)

FIG. 3. Effect of exhaustion of fixing bath on hypo
and silver content after washing. Eastman Super-XX
Panchromatic Negative Film, Type 1232. Fixed in
Kodak F-5. Washed 5 minutes at 68°F.

pH of fixing bath maintained at 4.1.

pH. of fixing bath increased with exhaustion to

5.5.

conditions with film or prints are favorable, the silver thiosulfate
complexes are not particularly harmful in the absence of hydrogen
sulfide in the air. However, if any unfavorable change occurs in
these conditions, the complexes decompose to produce a yellow
stain of silver sulfide which is proportional in intensity to the quantity
of silver retained. A study was therefore made of the effect of the
degree of exhaustion, the pH during exhaustion, and the degree
of washing on the relative quantities of silver and hypo retained by
the film.

Unexposed Eastman Motion Picture Super-XJ^ Panchromatic

July, 1943]

REMOVAL OF HYPO AND SILVER SALTS

Negative Film, Type 1232, was developed as recommended and then
fixed for four times the apparent "time to clear" (see "Time of Fixa-
tion," p. 25) in the Kodak F-5 potassium alum fixing bath without
the use of a rinse between development and fixation. The fixing
baths used were both fresh and exhausted to 100, 200, 300, and 400
feet per gallon. Similar tests were made with Eastman Motion
Picture Positive Film, Type 1301, and all tests with both emulsions
duplicated in the Kodak F-23 chrome alum fixing bath and in the
Kodak F-24 bisulfite-sulfite non-hardening fixing bath.

5 10 2.0 50

WASHING (MINUTES) 68°F

I 5 10 20 5O

WASHING (MINUTES) <be°p

FIG. 4. Effect of exhaustion of fixing bath on rate of removal of hypo by
washing. Eastman Super- JO" Panchromatic Negative Film, Type 1232.
Fixed in Kodak F-5.

Curve A— Fresh bath, pR = 4.1.

B — Exhausted to 100 feet per gallon, pR = 4.3.
C— Exhausted to 200 feet per gallon, pR = 4.7.
D — Exhausted to 300 feet per gallon, pR = 5.1.
E — Exhausted to 400 feet per gallon, pR = 5.5.

(a) pR maintained at 4.1.

(b) pR increased with exhaustion from 4.1 to 5.5 as shown above.

The curves in Figs. 3, 4, and 5 illustrate the effects of the degree
of exhaustion and changes of pH. of the F-5 fixing bath on the rates
of removal by washing of hypo and silver from processed Motion
Picture Negative Film, Type 1232.

Fig. 3 illustrates two important relationships between the hypo
and silver contents of the film after a given washing time of 5 minutes,
namely:

(1) If the pH of the fixing bath was maintained during exhaustion
at the pH of the fresh bath, the residual hypo content was essentially
constant while the silver content increased appreciably.

(2) If the £H of the fixing bath was allowed to increase (4.1 to
5.5) by carry-over of developer during exhaustion, the residual

CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

hypo content decreased to a low value and the silver was completely
removed at pH values greater than 4.9, which is the isoelectric
point of gelatin (see p. 43). The pH of the bath exhausted to 300
feet per gallon was 5.1.

Further experiments indicated that after a washing time of 30
minutes the hypo content was reduced to zero when the pH. of the
bath increased to 5.5, but when the pH was maintained constant at
4.1, the hypo content decreased to a certain small quantity not re-

s 10 20 30

WASHING (MINUTES) 68°

I 5 10 10

WASHING (MINUTES)

FIG. 5. Effect of exhaustion of fixing bath on rate of removal of silver
by washing. Eastman Super- JO" Panchromatic Negative Film, Type 1232.
Fixed in Kodak F-5.

Curve A — Fresh bath, pR = 4.1.

B — Exhausted to 100 feet per gallon, pR = 4.3.
C— Exhausted to 200 feet per gallon, pH. = 4.7.
D — Exhausted to 300 feet per gallon, pH. = 5.1.
E — Exhausted to 400 feet per gallon, pH. = 5.5.

(a) pH maintained at 4.1.

(b) pH. increased with exhaustion from 4.1 to 5.5 as shown above.

movable by further washing. Silver was retained only after fixation
in the baths exhausted to about 200 feet per gallon when the pYL
was maintained. The quantity of this residual silver after a 30-
minute wash was approximately 20 per cent lower than after a
5-minute wash and remained constant even after two hours' washing.
These facts are substantiated in greater detail in Fig. 4. The
curves in Fig. 4(a) and (b) indicate the relative rates of removal
of hypo for increasing times of washing after fixation in baths ex-
hausted to varying degrees (1) with the pH maintained, and (2)
at increasing pYL values in the range 4.1 to 5.5. An increase in pH

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 23

increased appreciably the rate of removal of the hypo but, after
fixation in the baths exhausted to about 200 feet of 35-mm film per
gallon and with the pH maintained, the hypo content could not
be reduced entirely to zero by any amount of washing.

The curves in Fig. 5 (a) and (b) show a similar effect of pH on the
rate of removal of silver, namely, that above a degree of exhaustion
of approximately 200 feet per gallon the silver can not be removed
entirely by washing when the £H is maintained.

It is therefore apparent that after a certain degree of exhaustion,
if the pH of the fixing bath is maintained constant, neither the hypo
nor the silver is completely removable by washing. A study of
the relative quantities of hypo and silver retained after fixation
in baths exhausted to different degrees in the range from 250 to
500 feet per gallon showed that the retention of silver approximately
paralleled that of the hypo.

The curves in Figs. 4 and 5 show that an increase in the £>H of
the fixing bath to a value above 4.9 permitted the complete removal
of the hypo and silver. Complete removal may also be accomplished
by bathing the film in an 0.03 per cent ammonia solution (1 cc of
28 per cent ammonia per liter) following washing of the film or by
the use of a fresh second fixing bath as described later.

In general, similar results were obtained when a chrome alum
fixing bath (Kodak F-23) was used. The hypo content decreased
with time of washing much more rapidly than as indicated in Fig. 4,
except for a small quantity retained by the film following fixation
in exhausted baths, when the residual silver and hypo contents were
somewhat less than those retained after fixation with exhausted
potassium alum baths. However, prolonged washing removed some
of the residual silver and hypo retained after chrome alum fixation
but had little effect on that retained after potassium alum fixation
when the pH of the bath was maintained.

With the bisulfite-sulfite non-hardening fixing bath, there was
no retention of hypo or silver following any degree of exhaustion,
and the hypo was removed somewhat more rapidly than after fixing
with chrome alum baths.

Data from experiments with finer-grained and more thinly coated
films, such as Eastman Motion Picture Release Positive Film,
Type 1301, and Fine-Grain Release Positive Film, Type 1302,
indicated that the same general effects were obtained but to a lesser
degree than with the high-speed negative film, Type 1232. A factor

CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

of four times the apparent "time to clear" was also used for the
time of fixation with these films.

(c) Effect of Original pH of Fixing Baths on Removal of Silver
from Film. — Figs. 4 and 5 show that complete removal of silver
and hypo was possible when the pH of the F-5 fixing bath was
allowed to increase during exhaustion to values above 4.9. When
the pH was maintained, the silver content of the film increased with
exhaustion. Tests were made to determine the effect of the pH of
different fixing baths, when maintained during exhaustion, on the
silver retained.

The fixing baths used were F-5 at pH = 4.1, F-10 at pH = 4.6,

QO4

003

001

125 250 375 5OO

DEGREE OF EXHAUSTION : FEET 35mm. FILM PER GALLON

FIG. 6. Effect of fixing bath pR on retention of silver by films
when original />H value is maintained during exhaustion. East-
man Super-ZZ Panchromatic Negative Film, Type 1232. Washed
20 minutes.

F-6 at £H = 4.9, and F-23 at £H = 3.1 and these were exhausted to
125, 250, 375, and 500 feet of 35-mm Super-^X Panchromatic
Negative Film, Type 1232, per gallon. The film strips washed for
20 minutes in the apparatus described in Fig. 1 were spot-tested
with sodium sulfide and the transmission densities of the silver sulfide
spots determined. The relative silver contents expressed in these
density units were plotted against the degrees of exhaustion as shown
in Fig. 6.

The curves show that less silver was retained as the pH of the
bath increased from 4.1 to 4.9 and that somewhat less silver was
retained by film fixed in an exhausted chrome alum bath.

(6) Replacement of Sodium Thiosulfate with Ammonium
77ii'osu//0te.— Equimolecular (14.4%) and semimolecular (7.2%)
concentrations of ammonium thiosulfate were substituted for the

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 25

sodium thiosulfate in the Kodak F-5, F-23, and F-24 solutions and
these baths compared with the regular formulas. The addition of am-
monium thiosulfate to the baths increased the pH somewhat so that
an adjustment to the pH of the regular baths was necessary.

With substitution in the F-5 bath, washing tests indicated that
after fixing in the 7.? per cent ammonium thiosulfate bath the
rate of removal of hypo was equal to that with the regular bath
but, after fixing in the 14.4 per cent bath, the rate was approximately
30 per cent greater. No differences were measurable between
sodium and ammonium thiosulfate in the case of the chrome alum
(F-23) or non-hardening (F-24) fixing baths. With respect to
silver, any differences were so small that they were not detectable
by the sulfide test.

EFFECT OF VARIOUS FACTORS

(/) Time of Fixation. — Tests were made with developed Eastman
Motion Picture Super- JO" Panchromatic Negative Film, Type 1232,
and Eastman Motion Picture Release Positive Film, Type 1301,
in both fresh and exhausted sulfite- bisulfite (F-24), potassium alum-
boric acid (F-5) and chrome alum (F-23) fixing baths. The baths
were exhausted to 125, 250, 375, and 500 feet per gallon with (a)
the £H maintained at the pH of the fresh bath, and (b) the £H
increased by carry-over of developer. The times of fixing used
were 2, 4, 6, and 10 times the apparent "time to clear" in each bath.
All test strips were washed for 15 minutes.

The "time to clear" of an emulsion is a somewhat variable factor
and dependent upon (a) the nature and intensity of the incident
light used to observe the clearing point (by refraction), and (b) the
ability of the individual to judge the clearing point. It is particularly
difficult to determine in the case of exhausted fixing baths because
of the very low rate of conversion of the halides to soluble com-
plexes. For these reasons the term "apparent time to clear" was
preferred.

The most satisfactory method of viewing was to direct a beam of
tungsten light between the film and a black background at an angle
of approximately 45 degrees to the background. The most accurate
"time to clear" determination required uniform agitation such that
the conversion of the halides was uniform over the entire emulsion
area. Relative clearing and fixing times should be determined at a
fixed temperature, for example, 68°F.

CRABTREE, EATON, AND MUELHER [j. s. M. P. E.

Under average darkroom conditions the results were usually
within 5 per cent when uniform agitation was employed and, al-
though tungsten light provided the best lighting conditions, the
light from a Series OA, 1, or 3 safelight, although less intense, did
not alter the "apparent time to clear" when transmitted rather
than reflected.

Since the removal of the last traces of residual silver is necessary
for archival purposes, tests were made with the F-5 fixing bath and
the negative film, Type 1232, to determine the best time of fixing

' (I) F-5 EXHAUSTED 375 FT. PER GAL pH MAINTAINED AT4

(2) F-5 EXHAUSTED 375 FT PER GAL pH AT 5.2S

(3) F-5 FRESH pH4.l

(4) F-5 FRESH pH 525

MULTIPLES OF "TIME TO .CLEAR11 IN F-5 FIXING BATH

FIG. 7. Effect of increasing time of fixation on the
residual silver content of film with fixing bath pH main-
tained at 4.1; with fixing bath pH. at 5.25. Kodak
Fixing Bath F-5. Eastman Super-JO" Panchromatic
Negative Film, Type 1232.

to accomplish this. The fresh fixing bath at pH = 4.1 was compared
with the fresh bath adjusted to pH — 5.25, with exhausted .F-5
at pH = 5.25, and with exhausted F-5 adjusted to pU = 4.1. The
curves in Fig. 7 show that (a) either a fresh or exhausted bath at a
pH above 4.9 permits the removal of the last traces of silver from
the negative film after fixing for twice the apparent "time to clear"
and (b) a fresh bath at its original pH (4.1) required four times the
apparent time to clear in order to make complete removal of the
last traces of silver possible, but an exhausted bath when adjusted
to pH 4.1 or to any value below 4.9 caused the retention of a con-
siderable quantity of silver. Similar results were obtained with the

July, 1943]

REMOVAL OF HYPO AND SILVER SALTS

positive film, Type 1301, except that the quantities of silver retained
were somewhat less.

The actual difference in the quantities of silver retained after
fixing for twice and four times the "time to clear" in the F-5 fixing
bath at £H = 4.1 is admittedly small and may be of no practical
significance. However, since removal by washing of the last traces
of silver was desired, a fixing time of four times the apparent time
to clear was used in both fresh and exhausted baths throughout
this investigation.

When the times of fixing were extended to six and ten times
the apparent "time to clear," the Super-^JY Negative film, Type

0.09
0.08
GOT

0.05

002
001

EXHAUSTION pH VALUES

FRESH 4-. I
1 25 FT /GAL. 4.5O
25OFT/GAL. 4.9O
375 FT/ GAL. 5.25 'Ox;

500 FT/ GAL. S.fcO

'EXHAUSTION
pHs.

125 25O 375 BOO

DEGREE OF EXHAUSTION: FEET 35mm FILM PER GALLON

FIG. 8. Silver retained after increasing times of fixation in
exhausted baths. Kodak Fixing Bath F-5. Film washed 15
minutes. Eastman Super-JOf Panchromatic Negative Film,
Type 1232.

1232, retained an almost constant quantity of silver after fixing in
an exhausted bath with the £H maintained at 4.1, as shown in Fig. 7,
but retained no silver when the £H was greater than 4.9.

It was of interest to determine the extent of the retention of silver
at various stages of the exhaustion life of a fixing bath when the
£>H was maintained at 4.1 and when it was allowed to increase by
addition of "carry-over" developer. The data and curves for tests
made with Eastman Super-JO Negative Film, Type 1232, are given
in Fig. 8 in which the relative silver contents are plotted in density
units obtained by reading silver sulfide spots as previously described.
Three facts are evident, namely, (a) when the pH was below 4.5,
the silver retained increased with exhaustion, (b) when the p*K of the
baths reached 4.9, the silver content was almost zero and at pH

CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

= 5.25 no silver was retained, which verifies the data illustrated
in Figs. 4 and 5, and (c) there was very little variation in the
quantity of silver retained after fixing for times longer than four
times the time to clear.

The curves in Fig. 9 illustrate the results of similar experiments
made with Eastman Motion Picture Release Positive Film, Type
1301. Three facts are evident from these curves, namely, (/) when
the pH during exhaustion was allowed to increase to 4.9 only a
very minute trace of silver remained in the sample fixed for ten
times the apparent "time to clear," (2) when the pH was main-

D 0.10

£ 0.09

5 008

^ O.OT

| 0.06

8 0.05

u 0.04-

5 001

£ ooz

w ooi

FRESH

125 250 375 50O

DEGREE OF EXHAUSTION. FEET 55nrm. PER. GM.LOK1

FIG. 9. Silver retained after increasing times of fixation in
exhausted baths. Kodak Fixing Bath F-5. Film washed 15
minutes. Eastman Positive Film, Type 1301.

tained below 4.9 the silver content increased with exhaustion but the
absolute quantities were less than those retained by Super- JOT
Negative Film, Type 1232 under the same conditions, and (3) with
the pYL maintained below 4.9 the quantity of silver retained in-
creased somewhat with the longer times of fixation for a given degree
of exhaustion.

With the Release Positive Film, Type 1301, the quantity of residual
silver increased somewhat after extended times of fixing (for example,
from 2 to 10 times the apparent time to clear) but no such increase
occurred with the Super-^Y^ Negative Film, for similar multiples
of the apparent time to clear. The actual time in minutes in the

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 29

fixing bath and the relationship of this time to the degree of hardening
of the film should explain this anomaly.

The apparent time to clear in fresh F-5 was approximately 30
seconds for the Release Positive Film, and 3 minutes 15 seconds for
the Super-XX" Negative Film. Therefore, four and ten times the
time to clear the films, Release Positive and Super-^O Negative,
in fresh and exhausted -F-5 baths were :

Release Positive Super-XX Negative

Type 1301 Type 1232

Fresh bath 4X 2 Min 13 Min

10 X 5 Min 32V2 Min

Exhausted bath 4X 4 Min 26 Min

10 X 10 Min 65 Min

The degree of hardening produced in an F-5 fixing bath increased
from about 150°F to near the maximum in 1 to 10 minutes and
reached the maximum in about 20 minutes (Fig. 10). It is believed
that the gelatin-hardener complex is responsible for the retention
of the silver and that as the degree of hardening increases the retention
of silver increases provided the £H of the bath is below 4.9. This
would suggest that the quantity of residual silver does not increase
with Super- XX Negative Film, because the maximum degree of
hardening is obtained in four times the apparent time to clear in a
fresh bath. However, it can increase with Release Positive Film
because the degree of hardening increased rapidly during the periods
of "four" and "ten" times the "time to clear."

Thus, from the standpoint of residual silver, extended times of
fixation in potassium alum baths at ^>H's below 4.9 have no ad-
vantage especially in exhausted or partially exhausted baths. To
remove the silver completely, the use of multiple fixing baths must
be considered.

When a fresh chrome alum (F-23) or fresh bisulfite-sulfite (F-24)
fixing bath was used, the rate of removal of hypo was so great as
compared with the rate when a potassium alum fixing bath (F-5)
was used that all of the hypo was removed in approximately 10
minutes following any time of fixation up to 30 minutes.

After fixation in exhausted chrome alum baths for the recom-
mended times, both silver and hypo as a complex were retained by
the film in approximately the same ratio and quantity as following
fixation in a potassium alum bath. However, with prolonged

CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

fixation in exhausted chrome alum baths there was no increase in
the quantity of retained silver thiosulfate complex.

(2) Use of Two Fixing Baths.— Several combinations of fixing
baths were studied to determine the effect on the rate of removal of
hypo, the degree of hardening, and the rate of elimination of the
silver from the processed film. A potassium alum hardening fixing
bath (Kodak F-5) was used as the first bath and either (a) a non-
hardening bath F-24 (/>H = 5.6), (b) a non-hardening bath, F-5
without alum (pH = 4.5), or (c) a chrome alum bath F-23 used as
the second bath.

s 7 10

TIME OF FIXATION (MINUTES)

FIG. 10. Effect of time of fixation on degree of hardening.
Eastman Motion Picture Positive Film. Type 1301. Kodak F-5
Fixing Bath (fresh pU; 4.1).

When emulsion 1232 was fixed in each of these fixing bath com-
binations, the residual hypo content in the film varied considerably
for a given washing time as shown in Table IV. A time of 20 minutes
in the first bath (to insure a maximum degree of fixation in the
exhausted baths) and 5 minutes in the second bath was employed.

TABLE IV

Effect of Second Fixing Bath on Rate of Removal of Hypo

Time of
Washing
(Min) F-5 F-5: F-5

Hypo Content (Mg per Sq-In)
F-5: F-5
(No Alum) F-5: F-24 F-5: F-23

10
25

0.20
0.05

0.20
0.04

0.02
Nil

0.005
Nil

0.06
Nil

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 31

The F-5 (no alum), F-24, and F-23 combinations with F-5 in-
creased the rate of removal of hypo greatly but the two baths of
F-5 were no different from F-5 alone. The degree of hardening was
equal in the F-5 and the F-5:F-5 combination but increased some-
what with exhaustion when using the F-5 followed by the F-23.
The hardening was decreased slightly when using F-5 followed by
F-24.

When exhaustion studies of the F-5: F-24 combination were made
it was found that the F-24 bath began to sludge after the bath was
only half exhausted. This difficulty was overcome (a) by using
an intermediate water rinse, (b) by using the F-5 fixing bath with
the alum omitted as the second bath, or (c) by lowering the pH value
of F-24 from 5.6 to 4.5 by the addition of acetic acid. When (c)
was employed the rate of removal of hypo was the same as with the
F-5: F-5 (no alum) combination. In this manner sludging did not
occur during the exhaustion life of the bath.

The use of F-6 as a second bath was very effective for hypo re-
moval, the hypo content of the film being 0.04 milligram per square-
inch after 10 minutes' washing. However, with this combination
(F-5: F-6) it was necessary to maintain the £H of the F-6 bath at
4.9 to 5.5 or its effectiveness would be lost because of a lowering
of the pH by the carry-over of the more acid F-5 fixing bath.

The silver content of the film was essentially reduced to zero
throughout the exhaustion when a second fixing bath was used for
2 to 5 minutes after the first F-5 fixing bath, regardless of the com-
position of the second bath.

It has been shown that when the degree of exhaustion of a single
bath (pH maintained) exceeded 200 feet of 35-mm. film per gallon,
silver was permanently retained by the film even after prolonged
washing. A second fixing bath should therefore be used and may
be exhausted to the point where silver is permanently retained by the
film.

When the pH of the first bath was maintained during exhaustion
the pH of the second bath did not change appreciably, but if the
pH of the second bath was low (e. g., F-5 at £H = 4.1) the degree of
exhaustion was limited by the silver retained by the film. On the
other hand, if the pH of the second bath was above £H = 4.9, the
degree of exhaustion was limited only by other factors such as sludg-
ing properties.

The relationship between the quantities of silver in the fixing

CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

bath and the silver retained by Eastman Super-XJf Negative Film,
Type 1232, is shown in Fig. 11 when two 7^-5 fixing baths were used
with the pH maintained at 4.1. It is apparent that the silver
content increases very rapidly in the first bath from the start of the
exhaustion and increases rapidly in the second bath only after 500
feet per gallon have been fixed. The silver content of the film in-
creased rapidly after fixation in the first bath, but following the
second bath, the content was zero until 250 feet per gallon were

125 25O 375 5OO 625 75O 875
PEGREE OF EXHAUSTION FEET 35mm. FILM PER GAL.

FIG. 11. Effect of exhaustion on concen-
tration of silver in first and second fixing
baths and in film fixed in these baths.
Eastman Motion Picture Super-.X'.X" Pan-
chromatic Negative Film, Type 1232.
Kodak Fixing Bath F-5. £H maintained.
Film washed 15 minutes.

fixed when it began to increase. The exhaustion life of this com-
bination of baths is dependent upon the proposed use of the proc-
essed film.

The use of any single bath or combinations of baths which have
pH values higher than pH — 4.9 prevents the retention of silver.

(3) Effect of Separated Hardening and Fixing. — A study was
made of the removal of hypo and silver when the hardening and
fixing operations were performed in separate baths. Negative
film, Type 1232, was hardened in a potassium alum bath which was
essentially F-5 without hypo for 10 minutes and then fixed in fresh

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 33

F-5 without alum for 10 minutes.* These operations were then
reversed and a comparison made with an emulsion processed (/)
in F-5 and (2) with a chrome alum hardening stop bath (SB-3) in
combination with a bisulfite-sulfite non-hardening fixing bath (F-24).

The analyses indicated that in the case of potassium alum harden-
ing baths hardening should take place before fixation to obtain the
best conditions for effective hypo removal. The most effective
combination was the chrome alum hardening bath (SB-3) followed
by the bisulfite-sulfite non-hardening fixing bath but this combina-
tion was no better than the use of a chrome alum fixing bath (F-23)
alone. However, tests with shorter times of washing in a less
effective washing system than that illustrated in Fig. 1 showed that
the SB-3: bisulfite-sulfite fixing bath combination was more effective
than F-23 alone. When exhausted fixing baths were used, the
retention of silver paralleled that of the hypo.

(4) Temperature of Processing. — The results of several experi-
ments with various films indicated that for a fixed washing tempera-
ture large temperature differences between the developer or fixing bath
and the wash water resulted in only small differences in the rate
of elimination of hypo and no differences in the rate of elimination
of silver.

WASHING

(1) Effect of Nature of Water: (a) pH of the Wash Water.— The
pH of the wash water has a very definite effect upon the rate of
removal of hypo as shown in Table V. Eastman Fine-Grain Release
Positive Film, Type 1302, was developed, fixed, and washed for 5
minutes at 65°F in tap water at a />H of approximately 7.0, and then
further washed by bathing in trays of water at different pH values.

TABLE v

Effect of pH of Wash Water on Rate of Removal of Hypo (Potassium Alum Fixing

Bath)
Eastman Fine Grain Release Positive Film, Type 1302

Concentration of Hypo (Mg per Sq-In)
£H 2 Min Washing 5 Min Washing

3.4 0.13 0.07

5.4 0.09 0.05

8.0 0.04 0.02

10.0 Nil Nil

* Formulas of this type are necessary because those similar to the non-harden-
ing F-24 fixing bath sludge when only one-half exhausted.

34 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

It is seen that an increase in pH of the wash water caused a de-
crease in the time required to eliminate a given quantity of hypo
from a given emulsion. This fact is of practical importance, es-
pecially where an alkaline water supply is used, and is contrary
to the claims of D. K. Allison12 that washing with water adjusted
to the isoelectric point of the gelatin will produce the most efficient
hypo removal, but it substantiates the results of Sheppard and
Houck.13

The most convenient and useful alkali for this purpose is am-
monia. In an experiment comparing the treatment of film in am-
monia after fixation in a potassium alum bath with fixation in a
chrome alum bath, the results showed that the ammonia treatment
has an effect equal to that of chrome alum in permitting hypo re-
moval. Super-^ Negative Film, Type 1232, was fixed in F-25,
rinsed for 2 minutes, bathed in 0.03 per cent ammonia solution
(pH — 10.2, and washed with film samples fixed in F-25 and in
the chrome alum F-23 bath. The results are given in Table VI.

TABLE VI

Effect of Dilute Ammonia Bath After Fixing on Hypo Removal

Hypo Content (Mg per Sq-In)
Fixing Bath Treatment 5 Min 15 Min 30 Min

Potassium alum ( F-25} 0 . 56 0 . 24 0 . 08

Potassium alum (F-25} 0.03% Ammonia Nil Nil Nil

Chrome Alum (F-23} 0.005 Nil Nil

When film samples were washed in the same apparatus with the /?H
of the water maintained at approximately £H-9.5, the rate of removal
was almost as great as indicated in Table VI.

TABLE VII

Effect of Ammonia on Degree of Hardening (Emulsion 1232}

Concentration of Melting Point (°F)

Ammonia 2 Min Bathing 5 Min Bathing 10 Min Bathing

(%)

0.56 161 140 100

0.28 174 166 126

0.14 182 176 154

0.07 186 182 172

0.03 194 192 190

0.00 210 210 210

The hardness of the gelatin film is affected by this alkaline treat-
ment but not to any serious extent if the concentration of alkali
is not excessive. From Table VII it is seen that ammonia used

July, 1943]

REMOVAL OF HYPO AND SILVER SALTS

at the concentration recommended (0.03%) is entirely satisfactory,
at least for times of treatment up to 10 minutes.

(b) Temperature of Wash Water. — Previous studies on the removal
of hypo by washing have shown that the rate of removal increases
appreciably as the temperature of the wash water increases.2 The
curves in Fig. 12 for Eastman Motion Picture Super-XX Panchro-
matic Negative Film, Type 1232, are representative of the curves for

15 30 40

-HME OP WASHING -MINUTES

FIG. 12. Effect of temperature on rate
of removal of hypo. Eastman Motion
Picture Super-JOT Panchromatic Negative
Film, Type 1232.

the entire series of films tested. It is evident that an increase in the
washing temperature produced an increase in the rate of removal
of hypo from the film and that the effect is greatest for the shorter
washing times. For example, an increase in temperature of the
wash water from 41° to 75 °F doubled the rate of removal of hypo
for a 15-minute washing time, the actual quantity being reduced
from 0.32 mg per sq-in to 0.16 mg per sq-in. Such differences in
the rate of removal are of practical significance, especially where
the available time for washing is short and the temperature of the
water supply is low.

36 CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

(c) Chemical Constituents in Water. — The degree of purity of the
water supply is of primary importance when washing photographic
materials for archival purposes because it is obviously useless to
treat photographic images in water containing chemicals which are
harmful to the image.

Distilled water, rain water, or water from melted ice or snow is
satisfactory. Many city water supplies are suitable but their
composition should be checked carefully before use. The most
common impurities in water may be grouped as follows:14

(1) Dissolved salts which produce hardness such as bicarbonates,
chlorides, and sulfates of calcium and magnesium. These are not
dangerous from the standpoint of effect on the image but as a visible
scum which reduces the transparency of the film. It is important,
therefore, to squeegee the film thoroughly just previous to drying.

(2) Suspended matter which may consist of mud, iron rust, free
sulfur, decayed vegetable matter, or biological growths. These
should be removed by filtration.

(3) Dissolved extracts which are usually colored yellow or brown.
Such coloring matter often becomes mordanted to the film or paper
which has been hardened with alum causing stains but this staining
may frequently be overcome by fixing in a non-hardening fixing
bath free from alum.

(4) Dissolved gases such as air, carbon dioxide, and hydrogen
sulfide. Waters containing hydrogen sulfide are also apt to contain
colloidal sulfur which is retained by the film and ultimately reacts
with the image.

(2) Effect of Turnover of Water. — A good washing system was a
prerequisite to this investigation and, although no detailed con-
sideration of the mechanics of washing is included here, it seemed
advisable to consider in a general way the factors involved in washing
in order (a) to insure the most effective washing conditions in an
experimental washing device, and (b) to establish the general con-
ditions to be satisfied in practice. The rate of renewal of water at
the surface of the material being washed has been claimed an im-
portant factor.

The turnover is dependent upon the input of water and the di-
mensions of the vessel. In very small washing units, such as small
diameter tubes, very shallow tanks, etc., the turnover, with sufficient
input, provides adequate agitation for the body of liquid. It is
practical to use an input great enough to provide both turnover

July, 1943 ] REMOVAL OF HYPO AND SILVER SALTS 37

and agitation. On the other hand, in large tanks, the agitation that
can be produced by inflow usually is negligible, giving rise to a more
or less stagnant condition in parts of the liquid.

It is apparent that the renewal of water at the surface of, say, a
strip of film can be made adequate in the small washing units by using
sufficient input but in the large tanks only by the use of mechanical
agitation.

During the removal by washing of hypo from photographic prod-
ucts the rate of diffusion of hypo from the film to the water depends
on the difference in concentration of hypo in the film and in the water.
The rate of washing is therefore greatest when the concentration
of hypo in the water is at a minimum, while the rate can be zero
when the concentration in the water is sufficiently great.

In order to obtain the greatest rate of washing as indicated above,
it is important to employ maximum turnover and maximum rate of
renewal at the film surface.

The experimental washing device used in this investigation
fulfilled thex conditions outlined. The turnover was 55 times the
capacity per hour and the agitation was sufficient to overcome
stagnation. A decrease in input increased the time required to re-
move a given amount of hypo from the film but the turnover and
degree of agitation were always adequate.

Curve A in Fig. 2 demonstrates the effect of different "inputs"
on the removal of hyp£> from 15-inch strips of 35-mm film in a given
washing time when suspended in a vertical glass tube of lV2-inch
diameter. This system was characterized by the fact that the
turnover caused adequate agitation and that renewal at the surface
approached a maximum.

Samples of Eastman Motion Picture Release Positive Film,
Type 1301, and Super-J^Z Panchromatic Negative Film, Type 1231,
were processed and, after fixing, were washed in tanks of large
volume as compared with the tube described above. At a given
input the tests were duplicated with and without air agitation, the
results indicating that air agitation of the wash water greatly in-
creased the rate of removal of hypo owing to the rapid renewal of
water at the surface of the film.

A third system considered was spray washing. Since in this
case no contaminated water could accumulate on the film, it was
evident that maximum turnover, agitation, and renewal at the

38 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

surface were approached. The tests indicated that such a system
was very effective in the removal of hypo.

WASHING OF PAPER PRINTS

Photographic paper prints, even after careful processing, are
more susceptible to deterioration (i. e., fading) than film negatives
or positives. Two factors influence this apparent susceptibility,
namely, (1) the high degree of reflection of the print reveals very
slight changes in the silver image, and (2) the structure of the print
is such that more hypo is retained per unit area than by an equivalent
area of film following the same fixing and washing procedure.

The hypo contents of commercially processed prints vary consider-
bly depending upon the type of washing equipment used but, in
general, they contain quantities indicated in Table I.

An earlier paper2 discussed in detail the removal of hypo following
fixation in fresh fixing baths and it was recommended that, in order
to insure the complete elimination of hypo, single- and double-weight
prints be washed for one-half hour to one hour, respectively, in
water at 60° to 70 °F and then be treated in a hydrogen peroxide-
ammonia eliminator.

The effect of exhaustion of the fixing bath on the removal of silver
and hypo was not considered, although the silver thiosulfates re-
tained in the print are largely responsible for the yellowing of the
highlights of faded prints. The experiments outlined above for
film were therefore repeated with photographic paper and it was
found that the removal of the last traces of hypo and silver from
prints is more complicated than in the case of films. In general,
photographic papers consist of (1) the paper base, (2) a baryta coating,
and (3) an emulsion coating, all of which retain hypo and silver.

Regular photographic papers were compared with a paper having
the base and baryta coating waterproofed and coated with a chloride
type of emulsion. The results showed that both hypo and silver
were more readily removed from such a waterproofed paper by wash-
ing than from the regular paper, indicating that the normal baryta
coating and paper base tend to retain a considerable quantity of
hypo and silver.

Experiments with non-waterproofed paper base alone bathed
in plain hypo, fresh and exhausted, showed that for a given washing
time the quantity of hypo and silver remaining in the paper base
increased with the time of treatment in the hypo bath and that

July, 1943 ] REMOVAL OF HYPO AND SILVER SALTS 39

the last traces of hypo and silver could not be removed by washing.
With a potassium alum bath (F-5), more hypo was retained than with
a non-hardening bath (F-24). This difference was not due to the
presence of alum but to the difference in pH of the two baths, as
evidenced by the fact that the hypo content was the same when
F-5 was compared with F-5 minus alum and adjusted to the same
/>H. Ammonia baths caused an increase in the rate of removal but
an excessive time of treatment was necessary to bring about com-
plete removal.

Baryta coatings on both regular paper base and on glass were
tested. With the "paper plus baryta," more hypo was retained
than with the paper base alone. To determine the role of the
baryta, coatings on glass were compared with gelatin coatings on
glass.

In a plain hypo solution the baryta coating retained hypo which
was not readily removed by washing. When a potassium alum
fixing bath was used, a much greater quantity of hypo was retained
by the baryta which could not be removed by prolonged washing,
but the increased hypo retained under the same conditions by the
plain gelatin was washed out. Both the baryta and gelatin coatings
retained hypo and silver from an exhausted fixing bath when the pH
was maintained, but when the pH increased during exhaustion to
5.5 the baryta retained slightly less hypo and silver while the gelatin
did not retain any. It is apparent, therefore, that the removal of
hypo and silver from baryta is not affected by changes in the £H
of the fixing bath in the range 4.0 to 5.6 to the same degree as the
removal from gelatin.

A dilute ammonia solution, however, promoted the removal of
hypo and silver from either the baryta or the gelatin coatings while
a second fixing bath removed the silver.

The presence of potassium alum in the fixing bath and changes
in />H of the fixing bath effected similar changes in the rate of re-
moval of hypo from the paper emulsion coated on the waterproofed
base (with baryta coating) as obtained with Eastman Motion Picture
Positive Film, Type 1301.

When the regular paper base plus baryta plus emulsion (regular
photographic paper) was treated in non-hardening (F-24) and
hardening (F-5) fixing baths both at the original and increased pH
values, it was found that (1) />H values in the range of 4.0 to 5.6 had
little effect on the rate of removal of hypo and silver, (2) the rate

40 CRABTREE, EATON, AND MUEHLER tf. S. M. P. E.

of removal was greater after fixing in F-24 as compared with F-5,
only during the early stage of washing, and (3) small amounts of
residual hypo and silver in the base and baryta coating were not
removed by very prolonged washing. Adsorption of silver com-
menced with the first paper prints processed.

Bathing in ammonia solutions caused the complete removal of
hypo and silver from photographic paper only after very long times
of treatment and, therefore, could not be considered adequate in the
normal processing of prints.

When residual silver is mordanted it is apparently always combined
with a certain amount of thiosulfate. If these silver complexes
remain in the print, especially in the absence of excess hypo, early
decomposition to silver sulfide may result. This condition may exist
even after the hypo has been removed with the hypo eliminator2
because, following fixation in a moderately exhausted bath, the hypo
eliminator does not attack the silver complex as readily as it does
hypo. With increasing times of treatment in the eliminator the quan-
tity of residual hypo and silver decreases until eventually they
are completely removed but such treatment is usually too severe
for the finished print.

The most practical and efficient method of removing the last
traces of both silver and hypo from prints is to employ two or three
successive fixing baths. A second bath is imperative in any fixing
operation and a fresh third bath is imperative in the preparation
of permanent prints when the residual silver content must be zero.
The residual hypo is then removed by means of the hypo eliminator.

In the case of films, as shown in Fig. 11, silver was retained in the
film (with exhaustion) when the fixing bath or baths were main-
tained at a pH value below 4.9 but was not retained if the pH was
higher than 4.9. A similar study made with prints indicated a
retention of silver (to a lesser degree) when the baths were main-
tained below pYL = 4.9 but, at pH values above 4.9, the nature of
the fixing bath had very little or no effect on the removal of silver
from the prints. Fig. 13 shows the relative increase in the silver
content of the baths and prints when two F-5 fixing baths at pH
= 4.1 were used. It is evident that sixty to seventy 8 X 10-inch
prints per gallon can be processed free of residual silver by using this
combination of fixing baths.

In general, the effects of (1) the change of pH of the fixing bath,
(2) the use of a dilute ammonia solution, and (3) the combinations

July, 1943]

REMOVAL OF HYPO AND SILVER SALTS

of fixing baths recommended for the removal of silver and hypo
from film were of little practical value with prints because of the
mordanting effects of the baryta coating and paper base. However,
chrome alum fixing baths, which may be used if the resulting slight
green stain can be tolerated, and plain hypo baths provide conditions
for a very marked increase in the rate of removal of hypo and silver
by washing. This increase in the rate of removal is obtained, how-
ever, only during the first few minutes of washing. With exhausted
chrome alum baths traces of both silver and thiosulfate remain after
prolonged washing of prints as in the case of films.

t ,

O 2O 4O feO 8O IOO I2O I4O IfeO I8O

DEGREE OF EXHAUSTION 8XIO INCH PRINTS PER GALLON

FIG. 13. ^Effect of exhaustion on concentration of
silver in first and second fixing baths and in paper prints
fixed in these baths. Azo F-3. Kodak Fixing Bath F-5.
H maintained. Prints washed 20 minutes.

THEORETICAL DISCUSSION

When silver halides are fixed out from an emulsion by a sodium
(or ammonium) thiosulfate (hypo) fixing bath, they are undoubtedly
converted to complex silver thiosulfates, the exact composition of
the complexes varying with the degree of exhaustion of the bath.
The work of Bassett and Lemon,15 using silver nitrate solution,
would indicate that the maximum ratio of silver to sodium in the
complex formed in sodium thiosulfate solutions rich in silver is
represented by the formula NaAgs^OsV On the other hand,
Baines,16 using silver carbonate, found that the formula of the
complex in thiosulfate solutions rich in silver is

42 CRABTREE, EATON, AND MUEHLER [J. s. M. P. E.

References are cited by Baines to show the general agreement by
other workers on the composition of this complex.

Assuming that the initial ratio of silver to sodium in the complex
approaches a value of 3:1 or 1:1, this ratio is quickly changed by
virtue of dilution by the excess fixing bath diffusing through the
emulsion.

Much of the published literature states that the first reaction is
to form a difficultly soluble complex and that on prolonged fixation
this is changed to a more soluble one. However, it is now apparent
that when the milkiness of a pure silver bromide emulsion has dis-
appeared, the silver halide has been rendered completely soluble
and capable of being washed out.

This removal of silver complexes takes place in two stages, namely,
(1) the complex silver ions diffuse out of the gelatin film while in
the fixing bath, and (2) diffusion of both complex silver ions and
thiosulf ate ions takes place in the wash water.

The washing of photographic materials represented by (2\ above
is considered to be an exponential process provided there are no
impediments to normal diffusion of the hypo from the gelatin layer.
Hickman and Spencer7 reported a divergence from the exponential
curve, or a "tailing off" of the curve, when a potassium alum harden-
ing bath was used prior to fixation, and stated that potassium alum
retards the washing out of an electrolyte (not identified) .

The washing data in this investigation, when plotted logarith-
mically, verified the exponential process and the "tailing off" of
the curves in some cases. When potassium alum fixing baths were
used the divergence from the exponential was very marked but
with chrome alum baths, no "tailing off" occurred. However, with
exhausted potassium and chrome alum baths appreciable "tailing
off" occurred as a result of the retention of a complex silver thio-
sulfate ion.

With photographic papers the divergence from the exponential
was always large because of the effect of the baryta coating and
the paper base.

The primary concern in this study was the removal of the last
traces of thiosulfate and silver thiosulfate ions (which caused the
"tailing off" of the exponential washing curves) retained by the
material even after long times of washing.

The retention of very small quantities of hypo and silver which
in some cases are not removed by prolonged washing is undoubtedly

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 43

the result of adsorption of the thiosulfate and silver ions. Gelatin
as an amphoteric electrolyte does not combine with salts but with
ions. At £H values lower than the isoelectric point (/>H = 4.9)
the gelatin becomes more positively charged and has a greater
attraction for anions, such as the thiosulfate ion or a complex silver
thiosulfate ion, while the converse is the case at £H values greater
than the isoelectric point when the attraction diminishes for anions
but increases for cations.13 The conditions under which thiosulfate
and complex silver thiosulfate ions are adsorbed and the conditions
for their subsequent removal by washing are outlined in Table
VIII.

(1) Adsorption of Thiosulfate and Silver Thiosulfate Ions.
—The adsorption is governed by the following factors :

(a) The pH of the Wash Water. — Since the £H of the wash water
is usually above 7.0, it is evident that the />H of a film fixed in any
fixing bath at a £H lower than the isoelectric point will slowly ap-
proach the isoelectric point of the gelatin during washing, thus
permitting a greater rate of removal of adsorbed anions such as
thiosulfate ions. The higher the pH of the fixing bath the greater
will be the apparent rate of removal because there is less ion ad-
sorbed by gelatin from the higher £H fixing baths.

(b) The Composition, Degree of Exhaustion, and pH of the Fixing
Bath. — With fresh potassium alum-boric acid fixing baths, the time
required to remove completely the thiosulfate ion was much longer
than with non-hardening baths but an increase in the £H of the
fixing bath to />H = 5.0 produced an apparent increase in the rate of
removal of the thiosulfate ion.

Assuming that the hardening of gelatin by alum is due to the
precipitation of alumina or a compound with gelatin which will be
termed an "alumina complex," it is apparent that this complex
adsorbs thiosulfate ion in considerable excess over the amount ad-
sorbed by gelatin alone.

With used potassium alum-boric acid hardening fixing baths, the
last traces of thiosulfate and silver were not washed out when the
/>H was maintained (/>H = 4.1 with F-5) but were easily removed
when the $H increased to about 5.0 during the exhaustion. These
results would tend to indicate that the silver and thiosulfate were
adsorbed together as a negatively charged complex ion which washed
from the film when the pR was sufficiently high. The fact that this
complexion was not removed by extended washing at low pH values,

TABLE Vin

The Adsorption and Subsequent Removal of Ions from Processed Photographic Film

and Paper
Film

Type of Fixing Bath

Potassium alum baths, e. g.,

F-5, F-10, F-25
(a) Fresh

Mordanted Ion

s2or

(6) Exhausted

S203=

Chrome alum baths,

F-16, F-23
(a) Fresh
(6) Exhausted

Bisulfite hypo, e. g.t F-24
(a) Fresh

None

[Agz(S2O3)/-

Paper

S203-

Exhausted

Chrome alum baths
Potassium alum baths

(a) Fresh

(6) Exhausted /

As with F-24

Means of Removal

(1) Increase temperature of
wash water and agita-
tion of water

(2} Increase pH. of fixing bath
to value above isoelec-
tric point of gelatin,
e. g., use F-6

(3) Use dilute ammonia solu-
tion (0.03%)

(1) Increase />H above iso-

electric point, e. g.,
use F-6

(2) Use any second or third

fixing bath

(1) Use a second fixing bath

with pH above isoelec-
tric point, e. g., F-6

(2) Use a second fixing bath

minus potassium alum

(1) Increase pR of bath to

value above 5.0 (no
hardening at this value)

(2) Use a second or third fix-

ing bath ; chrome alum
or F-24

(1) Increase temperature of

wash water

(2) Increase agitation of

prints in water
(5) Peroxide-ammonia hypo

eliminator
[Ag-e(S2O3)vn~] (1) Any second or third fixing

bath followed by
Hypo eliminator

(2}

As with F-24

As with F-24 but }

much greater \ As with F-24
quantities

REMOVAL OF HYPO AND SILVER SALTS 45

whereas thiosulfate ion alone was removed (as with a fresh bath),
would suggest a difference in the mechanism of the adsorption of
plain thiosulfate ions as compared with silver thiosulfate ions when
adsorbed to the alumina complex.

The complex silver thiosulfate ion was adsorbed from baths at
constant pH below pH = 4.7 only if the degree of exhaustion cor-
responded to a value of at least 200 feet of motion picture negative
film per gallon. Since the composition of the sodium silver thio-
sulfate complexes in a fixing bath undoubtedly varies with the degree
of exhaustion, it is quite likely that for degrees of exhaustion above
the 200 feet per gallon stage the composition of the fixing bath is
such that it can no longer affect the complexes in the emulsion
sufficiently to prevent the adsorption of a complex silver thiosulfate
ion by the alumina hardening complex. This contention is sup-
ported by the fact that any adsorbed complex is removed completely
with a fresh hypo solution. If the degree of exhaustion and, there-
fore, the concentration of silver in the bath increases, it can be as-
sumed that the degree of adsorption of silver to the alumina complex
increases and likewise that the rate of diffusion of silver from the
gelatin decreases.

Whether or not the composition of the adsorbed complex silver
thiosulfate ion changes with increasing degrees of exhaustion is not
known but preliminary analyses have indicated that up to a degree
of exhaustion corresponding to 500 feet of Eastman Motion Picture
Panchromatic Negative Film, Type 1232, per gallon, the ratio of
silver to thiosulfate in the residual adsorbed complex ion is probably
one silver atom to one thiosulfate radical.

When comparing the adsorption properties of chrome alum with
potassium alum-hardened gelatin, in the case of a fresh fixing bath
having a low or negligible silver content, the thiosulfate ion is ap-
parently not mordanted to the chromium hardening complex but
is very appreciably adsorbed to the alumina complex. However,
when the silver concentration in the fixing bath reaches a critical
value corresponding to a degree of exhaustion of 200 feet of the
Negative Film, Type 1232, per gallon, traces of silver and thio-
sulfate are adsorbed both by the chromium and alumina complexes.
After chrome alum fixation the silver and thiosulfate concentrations
decrease on prolonged washing but remain constant after potassium
alum fixation, unless the ^>H of the fixing bath or wash water is in-
creased. These facts would indicate a difference in the mechanism

46 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

of adsorption of the thiosulfate ion, [Ag^^Os) yW] . With non-harden-
ing fixing baths (F-24), both silver and thiosulfate likewise wash
out more readily when the £H is allowed to increase as compared
with a maintained pH of 5.6.

(c) The Time of Fixation. — An emulsion is considered completely
fixed when it is possible to reduce the non-developed silver content
to zero by subsequent washing. With Eastman Motion Picture
Release Positive Film, Type 1301, on prolonged washing, it was
possible to remove the silver completely after fixing for the "time
to clear" but a much shorter washing time was adequate if the film
was fixed for the usually recommened twice the apparent "time to
clear" in a non-hardening fixing bath. However, when a potassium
alum fixing bath was used complete fixation was obtained only after
three to four times the apparent time to clear.

Exhaustion of a plain hypo bath (F-24) extended the washing time
but exhaustion of potassium alum baths prevented complete fixa-
tion even when the "time to clear" factor was much greater than
two. An increase in the />H of the fixing bath, however, facilitated
washing.

On the other hand, films such as Eastman Motion Picture Super-
XX Panchromatic Negative Film, Type 1232, containing silver
iodide, required a factor of four times the "time to clear" followed
by a washing time longer than was previously thought necessary
for the complete removal of silver. An increased />H was also
necessary when using exhausted potassium alum fixing baths to ob-
tain complete fixation.

When fixing times of four to ten times the "time to clear" were
used with Eastman Motion Picture Positive Film, Type 1301, and
Super- JOT Negative Film, Type 1232, in fresh and exhausted potas-
sium alum fixing baths, two facts were evident, namely, (1) the
the quantities of residual hypo and silver in the Positive Type 1301
film increased appreciably, and (2) no measurable increase in the
quantities of residual hypo and silver occurred with the Super-XX
Negative Film, Type 1232.

These effects are closely related to the effect of time of fixation on
the degree of hardening of the gelatin film. As the degree of harden-
ing increases with time, the concentration of alumina in the gelatin
increases and this, in turn, adsorbs an increasing quantity of thio-
sulfate ion or of a complex silver thiosulfate ion depending upon the
condition of the bath.

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 47

The hardening of gelatin by chrome alum is more rapid than by
potassium alum. The fact that no further adsorption of complex
silver thiosulfate ion occurred on prolonged fixation would also
indicate that maximum hardening was attained in a relatively
short time.

It has been suggested that the silver image, in some cases, may
retain small amounts of hypo even though the highlights are free
from hypo. Most developed images on film and paper contain
a trace of silver sulfide which is approximately proportional to the
silver density and is revealed as a yellow residual image on treat-
ment of the silver image with Farmer's reducer.17' 18> 19 Silver
sulfide under certain conditions is known to be a mordant for certain
dyes but experimental evidence has indicated that hypo is not
mordanted. The sensitive mercuric chloride test for film and the
quantitative determination of reducible sulfur in print images have
failed to reveal any difference in the amounts of hypo retained
by the non -image and maximum density areas of film or print
images.

(2) The Desorption of Thiosulfate and Silver Thiosulfate
Ions. — The adsorption of the silver thiosulfate complex may be
reversed in several ways, namely, (a) by raising the £H of the fixing
bath or wash water or both, and (b) by immersing the film in a fresh
fixing bath in which the silver-ion concentration is very low or equal
to zero.

Adsorbed thiosulfate ion is removed by raising the pH of the
fixing bath or wash water, or both. The effect of the pH increase
is probably to change the nature of the electrical charges on the
adsorbent and to release the attraction between the ions and the
adsorbent.

The results obtained with photographic papers may also be ex-
plained, for the most part, on the basis of an assumption of adsorption
of both thiosulfate ion and complex silver thiosulfate ion.

In the case of the emulsion layer, the explanation for the retention
of hypo and silver by film is directly applicable. However, ad-
ditional sorption occurs in the baryta coating, both thiosulfate ion
and complex silver thiosulfate ion being sorbed, but the changes
in ^>H, effective for the removal of these ions from either gelatin,
the alumina-gelatin hardening complex, or chrome alum-gelatin
complex, were not great enough to reverse the sorption of the ions.

48 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

This was accomplished only after bathing in ammonia solutions
for long times.

The hydrogen peroxide-ammonia hypo eliminator has a 'twofold
effect on thiosulfate ions adsorbed to papers, namely, (a) the high
pH of the solution causes desorption, and (b) the desorbed ion is
oxidized to sulfate which is harmless. However, the adsorbed
silver complexes do not respond as readily to pH change, as men-
tioned above, while there is probably a slow reaction between the
adsorbed ion and the peroxide-ammonia solution. These silver
complexes, however, are very readily desorbed in hypo solutions.

TABLE IX

Suggested Maximum Permissible Concentration of Hypo

Commercial Use Archival Use

Films (Mg per Sq-In) (Mg per Sq-In)

Eastman Motion Picture Films

Fine-Grain Duplicating Positive Film, 0 . 02 0 . 005

Type 1365

Fine-Grain Release Positive Film, 0.05 0.01

Type 1302

Super-JO" Panchromatic Negative 0.20 0.05

Film, Type 1232

Photofinishers and Amateurs 0 . 15-0 .25* 0 . 05
Eastman X-Ray Films

No screen 0.40-0.50* . 0.10

Blue brand 0 . 25-0 . 40 * 0.05

Industrial type A 0.15-0.25* 0.05

Prints

Double Weight 0 . 20-0 . 25 Nil

Single Weight 0 . 10-0 . 15 Nil

* The coatings on many of these films consist of either (a) emulsion on one side
and gelatin on the opposite side, or (b) emulsion on both sides fa-ray). The
above data represent the hypo content of the coating on only one side of the film
so that when employing the mercuric chloride test which determines the total
hypo, the values in the above table should be doubled.

PRACTICAL RECOMMENDATIONS

In view of the increasing use of fine-grain films and the greater
realization of the necessity for the perpetuation of photographic
records, very careful attention should be given to the operations of
fixing and washing.

If long life of the photographic image is not required, it is un-

July, 1943]

REMOVAL OF HYPO AND SILVER SALTS

necessary to remove the last traces of silver and hypo, so that in
practice we may have two requirements, namely, (1) commercial
fixing and washing for materials with an expected keeping life of a
few decades or less, and (2) "archival" fixing and washing which
implies complete removal of all substances which might affect either
the image or non-image areas during long-time storage.

TABLE x

Suggested Maximum Permissible Concentrations of Silver

pH of Fixing Bath Maintained below 4.9

Single Bath

Films Commercial Use Archival Use

(a) Fixing Bath 1 . 5 grams per liter (twenty- 0.2 gram per liter (two

five 8 X 10-inch films per 8 X 10-inch films per gal)
gallon)

0.01 mg per sq-in Nil

(6) Film

Paper

(a) Fixing Bath

(b) Paper

Films

(a) Fixing Bath 6 . 0 grams per liter (sixty to 3.5 grams per liter (forty

8 X 10-inch films per gal)

0.3 gram per liter (thirty 0.05 gram per liter (five

8 X 10-inch prints per gal) 8 X 10-inch prints per gal)

0 . 005 mg per sq-in Nil

Two Fixing Baths

No. 1

seventy 8 X 10-inch films
per gal)
0 . 5-1 . 5 grams per liter 0 . 2 gram per liter

Fixing Bath

No. 2
(&) Film 0.01 mg per sq-in Nil

Paper

(a) Fixing Bath 2 . 0 grams per liter (two hun- 0 . 80 gram per liter (seventy

No. 1 dred 8 X 10-inch prints 8 X 10-inch prints per

per gal) gal)

Fixing Bath 0 . 3 gram per liter 0 . 05 gram per liter
No. 2

(b) Paper 0 . 005 mg per sq-in Nil

Since the future history of a processed negative or print is un-
known, it is always advisable to remove completely all residual
thiosulfates. It is, however, quite possible that slight tolerances
may be permissible even with archival films but this is not definitely
known. At the present state of our knowledge, the maximum
tolerances in the hypo and silver content of films and prints for

50 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

archival and commercial purposes given in Tables IX and X are
suggested. The tables also show the suggested maximum permissible
silver concentrations in the fixing bath or baths. This is important
because the concentration of silver in the bath is an indication of
the amount of silver likely to be retained by the film or print following
good washing.

It is evident from Table X that archival films and prints should
contain no residual silver to insure that the non-image areas remain
clear indefinitely. However, a slight general yellow stain does not
necessarily impair the usefulness of a film or print so that for com-
mercial purposes a slight quantity of residual silver can be tolerated.

Two general types of photographic paper prints should be con-
sidered, namely, (1) the fine-grain chloride type contact paper and
(2) the coarser-grain bromide type enlarging paper. The residual
hypo content of commercially processed fine-grain prints should
not exceed the values given in Table IX, but a somewhat greater
quantity of residual hypo (approximately 50 per cent greater) may
be tolerated in the bromide type prints because the coarser-grain
images are not so susceptible to fading as the fine-grain images.2
In the case of coarse-grain bromides for archival purposes, 0.05 to
0.10 milligram of hypo per square-inch could probably be tolerated.
This hypo content may be obtained without the use of a hypo elimi-
nator if the prints are washed for two hours in water at about 70 °F
and with optimum agitation. It must be remembered that other
factors2 influence the permanence of negatives and prints and these
have been considered when establishing the tolerances given above.

The processing recommendations given below, when carefully
followed, should effect the complete removal of silver and hypo from
films or plates. The complete removal of silver and hypo from
paper prints is always advised and complete hypo removal may be
accomplished by the use of the peroxide-ammonia hypo eliminator2
in addition to the recommendations given below. However, for those
whose equipment is not adequate to meet these demands, appreci-
able improvement over their existing methods of processing can be
effected by:

(7) Use of two or more fixing baths to reduce the silver content.

(2) Judicious choice of fixing baths to reduce both silver and
hypo contents.

(3) Adjusting the temperature of the wash water to 65° to 70°F
to accelerate washing.

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 51

(4) Use of more intensive agitation as with compressed air.

The quantities of residual hypo and silver indicated in the tables
are readily obtained under good fixing and washing conditions in the
usually recommended times of washing and, so far as we know,
can be considered to be safe, from a permanence viewpoint, if the
films and prints are to be stored under average conditions in temperate
climates. Under tropical or accelerated conditions, it is necessary
to remove all the silver and hypo because films and prints containing
amounts of hypo much less than those given may fade.

The term "commercial washing" has been used to denote the degree
of washing necessary to insure these maximum quantities of hypo
in both films and prints.

(1) Tests for Silver and Hypo.— Satisfactory tests for the pres-
ence of silver and hypo in film and paper are outlined below. These
have been modified slightly from the methods outlined on p. 14 in
order to meet commercial requirements.

(a) For Silver. — A drop of 0.2 per cent sodium sulfide is applied
to the margin of the dry or squeegeed film or print and removed after
2 to 3 minutes by careful blotting. Any coloration produced by
formation of silver sulfide in excess of a just visible cream tint in-
dicates the presence of silver in the film or paper. For careful
control a satisfactory standard is made by processing a blank sheet
of film or paper through two fresh fixing baths and a control test
made on this sheet. The stain produced is an indication of the
stain that might be formed in the highlights with adverse storage
conditions.

(b) For Hypo. — Many tests have been proposed in the literature
for the determination of hypo in both films and prints. The potas-
sium permanganate drip test is in common use for testing films and
prints during washing but its sensitivity is limited and it does not
determine the residual hypo in the washed material.

The mercuric chloride test described on p. 14 is very satisfactory
for use with either dry or wet film samples but it is necessary to clip
off a small piece of the film to be tested and it is not recommended
for measuring the total hypo content of prints. This test is particu-
larly useful when films are being prepared for archival storage. This
reagent is poisonous, should be handled carefully, and washed down
the drain with water when discarded.

An iodine spot test has been suggested20 which is dependent upon
the time required for the starch-iodine spot to decolorize. The

52 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

difficulty in application of the test was the reproducible measurement
of the volume of reagent used for the "spot" which must be constant.
The silver nitrate test is extremely sensitive and especially suited
to the measurement of hypo in prints. The spot-testing technique
is used but the accuracy of the test does not depend upon the volume
of reagent because the silver nitrate and hypo react in situ to produce
a definite quantity of silver sulfide since a great excess of silver
nitrate is used. The color of the spot varies from light yellowish
brown to dark brown depending on the hypo content. The test
may be used:

(1) To determine whether or not a print is entirely free from hypo
following the use of the peroxide-ammonia hypo eliminator, when
the procedure recommended in a previous paper may be used.2 A
dry print or an extra wet print may be spot- tested on the back with
silver nitrate and, if no hypo is present, no yellow stain should
appear. The excess water should be removed from a wet print be-
fore making the test.

(2} To determine the approximate quantity of residual hypo by
matching the spot with one of a series of spots prepared on single-
and double-weight prints having known hypo contents.

(2) The Fixing Process.— Complete fixation is necessary to in-
sure complete removal of both silver and thiosulfate even though the
washing system is efficient, and therefore the photographer needs
to know (a) what bath or baths insure rapid removal of hypo and
silver thiosulfate complexes in subsequent washing, (b) how long
the photographic material should be fixed, and (c) when the baths
should be discarded.

(a) Choice of Baths. — It has been shown that the use of single
fixing baths having pH values* lower than 4.9 retards, to a con-
siderable degree, the removal of residual hypo and silver complexes
during subsequent washing.

On the other hand, when the pH of a fixing bath is above the iso-
electric point of gelatin (pH = 4.9), no silver is retained by the
processed film after washing, irrespective of the composition of the
fixing bath, and the hypo is removed more rapidly during washing
provided fixation is complete. It is desirable, therefore, to employ,

* The />H of fixing baths may be determined either with glass electrode pH
meters, appropriate indicator solutions, or indicator test papers which may be
obtained from chemical apparatus supply houses.

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 53

whenever possible, fixing baths at pH values in the range 5.0 to 5.5.
A consideration of the fundamental properties of fixing baths showed
that potassium alum fixing baths containing boric acid or a salt of
the acid such as Kodak F-5, F-6, F-10, and F-25 could be adjusted
to />H values in the range 5.0 to 5.5 without changing the tendency
to scum, the sludge life, the sulfurization life, or the degree of harden-
ing. However, certain conditions must be fulfilled before their
use at these pH values is practical, namely :

(1) An acetic acid rinse bath must be used following development
(a) to dissolve calcium sulfite scum from the film, particularly when
low pH developers have been used, and (b) to prevent the pH of the
fixing bath from increasing to a value at which sludging and a lower
degree of hardening may occur. Potassium alum-boric acid baths
are sufficiently buffered to neutralize the acetic acid introduced
into the bath.

(2) It may be necessary to use a quick rinse following fixation to
avoid the formation of sludge in the wash water. This precipitation
is usually evident only during intermittent processing and may be
overcome by increased water flow and the use of the smallest possible
tank. Squeegees used following the fixing procedure are very
helpful.

Of the four baths considered, the F-6 bath approaches this desirable
pH range as can be seen from the following initial pH values :

F-5 — />H = 4.1
F-10—pU = 4.6
F-25—p?L = 4.2
F-6 — />H = 4.9

The pH of the F-6 bath is at the isoelectric point of gelatin and
when this bath is used only a minute trace of silver is retained while
hypo is very rapidly removed during washing. F-6, therefore, is
invaluable in the removal of silver and hypo when used either as a
single bath or as a second bath in a two- or three-bath combination.
As a result of the gradual addition of developer to a fixing bath
during use, the pU. value increases so that, even in the case of the
F-5, F-10, and F-25 baths (when used with normally alkaline de-
velopers and without an acid rinse bath or only a short water rinse),
a point is soon reached when they are as satisfactory as F-6 from a
hypo and silver retention standpoint. Beyond this point the harden-
ing properties continue to diminish so that it is desirable to maintain
the pH at this value (about 5,0) by replenishment with acid.

54 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

Although chrome alum fixing baths and hardening baths also
have advantages with respect to the removal of hypo and silver,
the F-6 bath is almost as effective in this connection and has less
tendency to scum and sludge while it does not lose its hardening
properties with age.

With this important general recommendation in mind, recom-
mendations of other fixing baths and fixing bath combinations are
given below for (1) continuous recirculating systems, and (2) non-
circulating systems.

(1) Continuous Recirculating Systems. — The use of a single fixing
bath, rather than two, in continuous recirculating systems such as
are used in many motion picture processing laboratories is entirely
practical because the hardening properties and the acidity (pH)
are maintained by replenishment, while the silver content is kept at a
minimum (approximately 1.0 gram per liter) by continuous electro-
lytic or sulfide recovery methods. The increasing iodide content
of these baths, especially when using high-speed negative materials,
does not seriously affect the retention of residual silver by the film.
The iodide content usually is such that it does not alter the fixing
time appreciably. Several different fixing baths are suitable for use
in these systems, namely:

(A) A chrome alum bath similar to Kodak F-23 is the most favor-
able because hypo is more readily removed after fixation in a chrome
alum bath than with potassium alum baths and no supplementary
treatments are necessary. The successful use of these chrome alum
baths is possible, however, only by careful adherence to correct
procedure as follows :

The baths should be revived periodically to maintain the chrome
alum concentration while the pH should be held between values of
3.5 and 4.0. When used intermittently, chrome alum baths should
be replenished immediately after use to prevent sludging.

Chrome alum baths tend to lose their hardening properties with
age even without use, while an excessive amount of alkali carried
over from the developer will tend to produce a greenish scum of
chromium hydroxide on the film or a sludge in the bath.10 These
sludging or scumming difficulties may be prevented by (/) the use
of squeegees between developer and fixing bath, (//) by adequate
replenishment, and (///) by maintaining the pH of the baths con-
stant by the addition of sulfuric acid. Suitable methods of main-
taining the pH of chrome alum baths have been described in the

July, 1943 ] REMOVAL OF HYPO AND SILVER SALTS 55

article "New Stop Baths and Fixing Bath Formulas and Methods
for Their Revival" (J. Soc. Mot. Pict. Eng., XXXVIII (April, 1942),
p. 353.

(B) A potassium alum bath of the type of F-5 or F-6 may be used.
F-5 a.t p*K = 4.1 requires a subsequent treatment of the film for at
least 3 minutes in an 0.03 per cent ammonia solution near the end
of the washing operation in order to insure complete hypo removal.
However, when F-6 at pH = 4.9 or F-5 modified to a pH of 5.0 to
5.5 is used, the ammonia treatment is not necessary.

With some potassium alum baths, particularly F-6, the alum of the
fixing bath carried into the wash water tends to hydrolyze, resulting
in sludge formation. This may be prevented by using either
a spray washer or a narrow tank (to insure rapid removal of water)
just prior to the passage of the film into the regular washing system.

(C) A non-hardening bath containing sulfite and bisulfite (pH =
5.6) may be used, followed by washing, and then hardening in an
alkaline formaldehyde solution,* and washing provided the processing
temperature is maintained at 68 °F or lower in order to prevent ex-
cessive swelling in the baths.

(2) Non- Circulating Systems (No Continuous Silver Recovery) ^
• — When a single fixing bath is used at a pH below 5.0 there is an
accumulation of silver on exhaustion and, in order to be sure that
no silver will remain in the final product after fixation in a partially
used bath, it is imperative to employ at least two separate fixing
baths in succession. By this means silver thiosulfates not removable
by washing are taken out of the film and in addition the time of
fixation may be reduced (see below, "Time of Fixation"). Although
many combinations of fixing baths are possible, the following are
suggested :

(a) Use of two bisulfite-sulfite non-hardening fixing baths in
succession such as Kodak F-24, followed by washing and then harden-
ing in the above formalin solution. The processing temperature
must be maintained at 68°F or lower to prevent excessive swelling.

(b) Use of two potassium alum hardening fixing baths similar
to Kodak F-6 at £H = 4.9, followed by thorough washing.

* 10.0 cc of 40% formalin per liter plus 5 grams of sodium carbonate.

56 CRABTREE, EATON, AND MUEHLER [j. S. M. P. E.

film is then immersed in an 0.03 per cent ammonia solution for 3 to
5 minutes and then washed for 5 to 10 minutes.

(d) Use of a potassium alum-boric acid bath, similar to Kodak
F-5, F-6, or F-25, as the first bath, followed by the first bath with
the alum omitted. When the second bath is transferred to the first
tank for use as the first bath, as described below, it is necessary to
add hardener. Besides removing silver thiosulfate, the non-harden-
ing second bath causes more rapid removal of hypo and prevents
the possible formation of alumina sludge in the wash water.

(e) High-temperature processing demands the use of chrome alum
baths which may be employed in the following combinations:
a chrome alum hardening bath (SB-4) followed by a non-hardening
fixing bath (F-24), or two chrome alum fixing baths (F-23).

To insure the complete removal of residual silver, the non-harden-
ing bath used in (a) should be discarded when it is half exhausted
with respect to silver content, otherwise two fixing baths should be
used in combination with the chrome alum hardening bath. The
half -exhaustion point is determined by the method described on p. 58.

(b) Time of Fixation: (1) Single Bath ''Time of Fixation." — When
the pH of a fixing bath is greater than 4.9, silver is not retained
by the film and the usually recommended time of fixing of twice
the "time to clear" is satisfactory as shown in Fig. 7. However,
when the pH is maintained below 4.9 it has been shown that the
use of a single bath is not practical because considerable quantities
of silver are retained by the film. Chrome alum fixing baths cannot
be used above pH = 3.8 to 4.0 because of sludging and loss of harden-
ing properties. Thus, with pH maintained below 4.9 it is necessary
to use at least two fixing baths in order to remove completely the
silver by washing.

(2) Time of Fixation with Two Fixing Baths. — Apart from being
impractical, the long times of fixation required in an exhausted
single bath with £H below 4.9 caused increased retention of silver
thiosulfate complexes by the film. A second fixing bath removes
the residual complexes retained from the first bath and permits a
shorter time of fixing in the first bath. The times given below are
based upon exhausted first baths and are not variable if the complete
removal of silver is desired.

For the present-day high-speed negative materials a minimum
time of 10 minutes (approximately twice the "time to clear" in an
exhausted bath) is recommended in the first bath and a minimum

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 57

time of 3 minutes in the second bath at 68°F. Minimum times of
5 and 3 minutes, respectively, are suggested for positive type emul-
sions. These times were arrived at from a consideration of the
minimum time to obtain (a) complete fixation, and (b) adequate
hardening.

Shorter times of fixation than those given produce a low degree of
hardening with the alum fixing baths and permit the accumulation
of too much silver in the second bath, thereby defeating the purpose
of the second bath. Longer times of fixation than 20 minutes,
especially in the first bath, permit the retention of greater quantities
of silver and hypo. With baths of low pH, if the total fixing time
exceeds 20 minutes, reduction of the silver image may occur.21

(c) When to Discard the Fixing Bath. — Assuming that the pH is
maintained and that there is no sludging or sulfurization, the fixing
properties cease to be satisfactory when the concentration of silver
in the bath exceeds a definite concentration because silver thiosulf ate
complexes are retained by the film. These critical concentrations
of silver are indicated in Table X and may be determined with the
Argentometer9 of Weyerts and Hickman. The ''Kodak Testing
Outfit for Fixing Baths"* has been adjusted to indicate the maximum
practical degree of exhaustion of a film fixing bath which corresponds
to a concentration of approximately 6.0 grams of silver per liter.

The Kodak Testing Outfit is particularly useful when two fixing
baths are used. When a positive silver test is obtained with the
first bath, it should be discarded. The second bath is then trans-
ferred to the first tank or tray to be used as the first fixing bath and a
fresh solution used in the second tank.

In cases of ordinary processing when archival storage is not being
considered, the preferred fixing procedure is to use two fixing baths,
but if only a single bath is used, it should be discarded when the
silver concentration increases to 6.0 grams per liter to avoid possible
changes in the film which might occur in a very short time of keeping
with quantities of silver greater than this.

In practice, the £H of a single bath usually increases to a degree
depending upon the developer carry-over, but, if the pH exceeds
4.9, no silver is retained by the film. However, the clearing time

* To determine the exhaustion life of the first bath, add 10 drops of the fixing
bath to 5 drops of the test solution B (from the Kodak Testing Outfit). An im-
mediate heavy yellow precipitate indicates that the bath is exhausted.

58 CRABTREE, EATON, AND MUEHLER [J. S. M. P. E.

is usually at the practical limit when the silver content is 6.0 grams
per liter and the bath should then be discarded.

In the case of high-temperature processing using a chrome alum
hardening bath and a non-hardening fixing bath, the fixing bath
should be discarded when half exhausted.*

(3) The Washing Procedure. — The absolute time required to
wash a given film emulsion is largely dependent upon the washing
equipment and conditions used. The more effective the washing
technique, the shorter the time of washing required to remove com-
pletely the hypo and silver.

Maximum and efficient removal of hypo and silver can be insured
by observance of the following precautions :

(a) Maintenance of an Adequate Rate of Renewal of Water at the
Film Surface. — In most cases neither the cascade nor the individual
tank systems using large tanks produces sufficient agitation or re-
newal of fresh water at the film surface to insure the maximum rate
of washing unless a large number of stages are used.

More rapid renewal at the film surface can be insured either by
mechanical or air agitation or by spraying the water onto the film
surface by a suitable arrangement of jets. It is preferable that the
film be entirely submerged but, if this is not practicable, it is very
important to insure a uniform flow of water at the film surface by
staggering the nozzles and to take precautions that sprockets, shafts,
chains, idlers, and other mechanical parts are adequately sprayed.

In order to insure maximum efficiency in washing, the volume of
the wash tank for a given flow of water should be as small as possible
so that the turn-over of the water is a maximum. With average
conditions of washing when using a potassium alum fixing bath
(pH less than 4.9), approximately one hour is required to wash out
completely the hypo from the thicker high-speed negative emulsions
such as Super- JO" Negative Film, Type 1232. It is apparent,
therefore, that satisfactory washing can not be attained with in-
efficient systems with a washing time of only 10 to 15 minutes.

(b) Adjustment of the pH of Wash Water.— The pH value of the
wash water may be adjusted by the addition of ammonia at a rate
sufficient to maintain the />H between values of 9.0 and 10.0. This
may be accomplished by (1) automatic pH control apparatus now

* Add 5 drops of test solution B to 5 drops of water, then add 10 drops of
fixing bath. A heavy yellow precipitate indicates that the bath is half exhausted.,

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 59

commercially available, and (2) addition of ammonia water at a
suitable rate by means of a constant-level device and a calibrated
orifice.

The film should be rinsed before entering the tank in which the
pH has been adjusted with ammonia; otherwise, when using a
potassium alum bath a sludge of alumina would be produced. The
water in the remaining tanks then washes the film free of hypo and
ammonia. Ammonia in all the tanks has no advantage over its
presence in one or two tanks. It is obvious that the use of several
narrow tanks is to be preferred to only a few larger tanks. The
use of squeegees will, of course, greatly minimize the quantity of hypo
carried into the rinse and wash waters.

(c) Control of Temperature of Wash Water. — The temperature
of the wash water should not be too low, the most useful and practical
range being 60° to 70°F.

(4) Fixing and Washing Paper Prints.— It is obvious that
certain steps must be taken to improve the commercial washing of
photographic prints in order to produce prints which do not contain
more hypo than the quantities previously indicated. In order to im-
prove the washing, the following relatively simple operations should
be adopted: (1) Raise the temperature of the wash water, (2) use
adequate mechanical agitation, (3) prolong the washing time, and
(4) employ the hypo eliminator2 if lower quantities of hypo are de-
sired.

The removal of hypo and silver from film by washing was greatly
improved by (a) adjusting the pH of the fixing bath to a value in
the range 5.0 to 5.5, (b) bathing in 0.03 per cent ammonia solution,
(c) using a chrome alum fixing bath or the F-6 potassium alum fixing
bath, and (d) using a two-fixing-bath combination in which the
second bath was non-hardening or at a />H value higher than 4.9.

However, with paper prints the above procedures assisted the
removal of hypo by washing only to a small degree and only during
the first few minutes of washing. Of these treatments the com-
bination of two fixing baths was the only one which assisted in the
removal of silver.

Recommended potassium alum fixing baths for use with prints
are Kodak F-l, F-5, and F-6. Prints should be fixed for a minimum
time of 5 minutes to insure thorough fixation in exhausted baths.
Longer times of fixation up to 15 to 20 minutes may be used without
affecting the silver image, but under these conditions greater quan-

60 CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

titles of hypo and silver are retained. When using more than one
fixing bath it is desirable to fix about 5 minutes in the first bath and
from 3 to 5 minutes in subsequent baths. It is never desirable to

FIXED IN BATH NO.)

MAXIMUM CONCENTRATION

OF SILVER
BATH NO. I

32 ** 9* iS2 200

8XIOINCH PRINTS PER GALLON

FIXED IN BATH NO.i FOLLOWED BY BATH NO. a

BATH NO 2
O.3 q

8 32 64 96 152 200

8XIO-INCH PRINTS PER GALLON

F1XEP IN BATH NO.* FOLLOWED BY BATH NO. 3

BATH NO. 3
O.iOqm*/ LITER

*2 44 96 182 ZOO

8XIO-INCH PRINTS PER GALLON

FIG. 14. Illustrating the relative quantity of residual silver in
prints when fixed in multiple baths. After fixing and washing, the
prints were stored at 110°F when the silver thiosulfates decomposed
to yellow silver sulfide. The quantity of silver sulfide stain is
therefore an indication of the probable appearance of the highlights
of the prints on prolonged storage. Note that the exhaustion life
of a single fixing bath is not greater than twenty-five 8 X 10-inch
prints per gallon, but with three fixing baths the life is at least one
hundred prints per gallon.

allow prints to soak for excessive times (30 minutes or upward) in
the fixing bath because this tends to retard easy removal of hypo by
washing and to reduce the image.

The intended use of the prints largely governs the method of

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 61

fixing to be employed. In order to obtain the most permanent
prints possible, for archival purposes, it is imperative that at least
two and preferably three fixing baths be used, preferably with a
rinse between baths. The baths should be used until the first bath
is exhausted as judged by the "Kodak Testing Outfit for Acid Stop
Baths and Fixing Baths."* Then the second and third baths are
used as the first and second baths, and the cycle is repeated.

Fig. 14 illustrates the relative silver sulfide stain produced by de-
composition of the retained silver thiosulfates in prints fixed in the
three baths during the processing of sufficient 8 X 10-inch prints to
give a positive silver test in the first bath with the Kodak Test Kit.
It is seen that a second fixing bath will permit the fixation of about
thirty 8 X 10-inch prints per gallon which contain no silver, while
the use of a third bath will permit the fixation of about one hundred
8 X 10-inch prints per gallon. The baths were exhausted to two
hundred 8 X 10-inch prints per gallon with samples taken out for
test as indicated. The silver content of the baths after this number
of prints was processed is indicated. These values were determined
with the Argentometer described by Weyerts and Hickman.9

Following thorough fixation in at least two successive fixing baths,
the prints should be washed, treated in the hydrogen peroxide-am-
monia hypo eliminator,2 washed, and further protected against
atmospheric conditions as recommended in the paper "The Elimina-
tion of Hypo from Photographic Images."2 The use of at least two
and preferably three fixing baths previous to the use of the eliminator
is imperative since the eliminator does not remove silver thiosulfates.
In the absence of thorough fixation, early decomposition of the
residual silver complexes to silver sulfide may occur causing staining
of the highlights of the print.

When a single fixing bath is used until exhausted as indicated
by the Kodak Testing Outfit, it contains about 1.2 to 1.5 grams of
silver per liter. Prints fixed in this solution will keep for a short
time only, especially under adverse storage conditions. The maxi-
mum concentration of silver in a fixing bath considered to be safe
for commercial purposes is approximately 0.30 gram per liter which

* To determine the exhaustion life of the first bath, add 5 drops of test solution
B to 5 drops of water and then add 10 drops of the fixing bath. The bath is ex-
hausted when a permanent heavy yellow precipitate forms. This test is designed
to measure the much lower critical concentration of silver in paper fixing baths.

62 CRABTREE, EATON, AND MUEHLER [J. S. M. p. E.

means that only about thirty 8 X 10-inch prints per gallon should
be fixed in a single bath.

It is therefore considered necessary, as well as more economical
and practical, to use two fixing baths in commercial processing.
By this means the first bath can be exhausted, before being dis-
carded, with one hundred fifty 8 X 10-inch prints per gallon of fixing
bath. This exhausted bath may then be replaced by a fresh bath and
when this bath is exhausted with one hundred fifty 8 X 10's per
gallon, the second bath may be used as the first bath. An alternative
is to exhaust the first bath which is then replaced by the second bath
and a fresh second bath employed. The exhausted bath should
contain about 1.2 to 1.5 grams per liter of silver and give a positive
test with the Kodak Testing Outfit.

A further saving in time, because of less handling, will result
from the use of three fixing baths, in which case four fresh first
baths may be exhausted before it is necessary to move the second and
third baths into the first and second positions, after which three more
fresh first baths may be used, and so on. This method is not satis-
factory for the complete removal of residual silver, but only when
0.30 gram of silver per liter in the fixing bath can be tolerated.

The use of multiple fixing baths may be simplified by the adoption
of a continuous countercurrent flow of the fixing bath through a
series of at least two tanks. This arrangement would eliminate the
necessity of (a) moving the tanks from one position to another,
(&) transferring the baths from one tank to another, or (c) replenish-
ing the bath in a single tank by flowing in fresh solution at a con-
stant rate. A countercurrent flow system would also reduce the
loss of silver usually incurred by the carry-over of partially ex-
hausted fixing bath into the wash water since the silver content of
the last fixing bath would be at a minimum.

It has been suggested that a fewer number of fixing baths contain-
ing much greater quantities of hypo (e. g., 60 per cent) could be
used. Tests made in this connection did not show any practical
advantages in the use of such baths.

To Summarize. — The above recommendations insure as well
as is known the absence of silver thiosulfate and free hypo in the
finished negative or print and, although in most cases, if the hypo
and silver contents are reduced to the permissible values suggested
in Tables IX and X, satisfactory permanency can be expected, it
is desirable to follow the procedure for complete elimination in

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 63

order to take care of possible inefficiencies in either the fixation or
washing procedures and of possible abnormal conditions of storage.

Although emphasis has been placed on the production of perma-
nent films and prints with respect to the silver image, it is of equal
interest and importance that the photographic base shall have
equal permanency.

Experience has shown that many high-grade book papers have
retained their original characteristics for several hundred years,
and aging tests made by the Bureau of Standards 22- 23 have indicated
that paper stock of the type used in photographic paper is as per-
manent as the high-grade book papers tested. It is, therefore,
reasonable to assume that the photographic paper base will keep, at
least, for two or three hundred years.

In the case of films free of residual hypo and silver and stored
at 50°F or lower those with nitrate film base will probably remain
unchanged for at least 100 years. It is recommended, however,
that films for record purposes be made on safety (acetate) base
since accelerated aging tests made by the Bureau of Standards1
have indicated a greater permanency for acetate as compared with
nitrate film base.

ACKNOWLEDGMENT

The authors are indebted to Mr. C. E. Ives for helpful suggestions
and to Mr. C. J. Kunz for assistance in the experimental work.

REFERENCES

1 HILL, J. R., AND WEBER, C. G.: "Stability of Motion Picture Films as
Determined by Accelerated Aging," Research Paper RP950, National Bureau of
Standards, December, 1936.

2 CRABTREE, J. I., EATON, G. T., AND MUEHLER, L. E.: "The Elimination of
Hypo from Photographic Images," /. Soc. Mot. Pict. Eng., XXXV (May, 1940), p.
484.

3 CRABTREE, J. I., AND IVES, C. E.: "The Storage of Valuable Motion Pic-
ture Film," /. Soc. Mot. Pict. Eng., XV (September, 1930), p. 289.

4 SIEBERT, VON OTTO: "Wann haben unsere Flatten und Bilder geniigend
gewassert?" (When Are Plates and Prints Sufficiently Washed?"), Das Atelier
des Photographen, 4 (1903), p. 62. Refers to work of Gaedicke. Cf. Photo
Woch., Feb. 13, 1900.

6 LUPPO-CRAMER : "Zum auswaschen der Fixier-losungen" ("On the Wash-
ing Out of Fixing Solutions"), Phot. Ind. (1917), p. 686.

6 ELSDEN, A. V.: "The Removal of Hypo by Washing with Water," Brit. /.
Phot., 64 (1917), p. 119.

64 CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

7 HICKMAN, K. C. D., AND SPENCER, D. A.: "The Washing of Photographic
Products— Part 3," Phot. J., 48 (1924), p. 539.

8 CRABTREE, J. I., AND Ross, J. F. : "A Method of Testing for the Presence of
Sodium Thiosulfate in Motion Picture Films," /. Soc. Mot. Pict. Eng., XIV
(April, 1930), p. 419.

9 WEYERTS, W. J., AND HICKMAN, K. C. D.: "The Argentometer — An Ap-
paratus for Testing for Silver in a Fixing Bath," J. Soc. Mot. Pict. Eng., XXV
(October, 1935), p. 335.

10 CRABTREE, J. I., AND RUSSELL, H. D. : "Some Properties of Chrome Alum
Stop Baths and Fixing Baths, Part I," J. Soc. Mot. Pict. Eng., XTV (May, 1930),
p. 483; "Part II," J. Soc. Mot. Pict. Eng., XTV (June, 1930), p. 667.

11 RUSSELL, H. D., AND CRABTREE, J. I.: "An Improved Potassium Alum
Fixing Bath Containing Boric Acid," /. Soc. Mot. Pict. Eng., XXI (August, 1933),
p. 137.

12 ALLISON, D. K. : "Accurate Laboratory Control — Part 3, pH in Processing,"
Internal . Phot., 9 (1937), p. 35.

13 SHEPPARD, S. E., AND HOUCK, R. C. : "The Influence of pH on Washing
Films after Processing," /. Soc. Mot. Pict. Eng., XXXI, (July, 1938), p. 67.

14 CRABTREE, J. I., AND MATTHEWS, G. E.: "Effect of the Water Supply
on Photographic Operations," Amer. Phot., XXI (1927), p. 634.

"BASSETT, H., AND LEMON, J. T. : "Sodium Thiosulfate-Silver Thiosulfate
System," J. Chem. Soc., Part II (1933), p. 142.

16 BAINES, H.: "The Chemistry of Fixation," Phot. J., 69 (1929), p. 314.

17 LUPPO-CRAMER: "Zur Konstitution der Negativsubstanz" ("On the Com-
position of the Negative Substance (Image)"), Phot. Korr., 49 (1912), p. 121.

18 LUMIERE, A., AND L., AND SfiYEWETZ, A.: "Sur la composition des images
photographiques obtenues par developpement et fixage des impressions latentes
du gelatino-bromoiodure et du gelatino-bromire d'argent" ("The Composition of
Photographic Images Obtained by Development and Fixation of Gelatin Silver
Bromoiodide and Silver Bromide Latent Images"), Bull. soc. franc., phot., 3
(1912), p. 36.

19 CRABTREE, J. I., AND MUEHLER, L. E.: "Reducing and Intensifying Solu-
tions for Motion Picture Film," /. Soc. Mot. Pict. Eng., XVII (December, 1931),
p. 1025.

20 GARY, E., AND WHEELER, A. H. : "Quantitative Tests for Residual Hypo,"
Amer. Phot., XXXVI (Jan., 1942), p. 16.

21 RUSSELL, H. D., AND CRABTREE, J. I.: "The Reducing Action of Fixing
Baths on the Silver Image," /. Soc. Mot. Pict. Eng., XVHI (March, 1932), p. 371.

22 RASCH, R. H., AND SCRIBNER, B. W.: "Comparison of Natural Aging of
Paper with Accelerated Aging by Heating," Bureau of Standards Journal of Re-
search, 11 (1933), p. 727.

23 RASCH, R. H., SHAW, M. B., AND BICKING, G. W.: "Highly Purified Wood
Fibers as Paper Making Material," Bureau of Standards Journal of Research, 7
(1931), p. 765.

BIBLIOGRAPHY

1890 DUNMORE, E.: "About Hypo," B. J. Phot., 37 (1890), p. 327. Warm
water is preferable to cold. Imperfect fixation is the most frequent

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 65

cause of fading prints. Two fixing baths are recommended with an inter-
vening rinse.

1893 GRUNDY, F. B., AND HADDON, A.: "On the Amounts of Silver and Hypo
Left in Albuminized Paper at Different Stages of Washing," B. J. Phot.,
40 (1893), p. 511. Silver thiosulfate complexes were not removed after
two or nineteen hours of washing. Claims that the earliest reference to
this fact was by JOHN SPILLER, Phot. News, 471 (1862), p. 471.

1902 LUMIERE, A., AND L., AND SEYEWETZ, A.: "Sur 1'elimination par lavage
a 1'eau de 1'hyposulfite de soude retinu par les papiers et les plaques photo-
graphiques" ("The Elimination of Hyposulfite of Soda from Papers and
Films by Washing with Water"), Bull. soc. fran$. Phot., 18 (1902), p. 251;
cf. B. J. Phot., 49 (1902), p. 392. The last traces of hypo were very
difficult to remove. Graphs are included. The vigorous retention of
hypo was attributed to adsorption by the paper.

1903 SIEBERT, VON OTTO: "Wann haben unsere Flatten und Bilder geniigend
gewassert? ("When Are Plates and Prints Sufficiently Washed?"), Das
Atelier des Photo graphen, 4 (1903), p. 62. Relative washing rates were
determined by testing the hypo in the wash water. Referred to work of
Gaedicke (Photographische Wochenblatt, 1900) who claimed that alum hard-
ened plates required excessive washing as compared with non-hardened
plates.

1908 LUMIERE, A., AND L. , AND SEYEWETZ, A.: "Entfernung des fixiernatrons
durch Waschen mit Wasser" ("Removal of Sodium Thiosulfate by Wash-
ing with Water"), Eder's Jahrbuch, (1908), p. 502. Increased tempera-
ture of the wash water caused an increased rate of washing.

1908 LUPPO-CRAMER: "Kolloid Chemie und Photographie," (1908), p. 133.
Silver thiosulfate complexes can only be washed out of films by hypo
solution.

1910 HAUBERRISSER, G.: "Uber das Entfernen von Fixiernatron aus photo-
graphischen Schichten durch Auswassern bei hoherer Tempera tur"
("Removal of Hypo from Photographic Layers by Washing at Elevated
Temperatures"), Phot. Rund., 24 (1910), p. 91. An increase in tempera-
ture of the wash water from 60° to 70° C produced a considerable increase
in the rate of removal of the hypo.

1912 LUPPO-CRAMER: "A Note on the Difference of Time for the Removal of
Hypo from Plates Fixed in Ordinary and Acid Fixing Baths," Brit. J.
Phot., 59 (1912), p. 638. An acid fixing bath '(non-hardening) washed out
much more slowly than a plain fixing bath.

1917 ELSDEN, A. V.: "The Removal of Hypo by Washing with Water," Brit. J.
Phot., 64 (1917), p. 119. Only neutral thiosulfate was used and no ac-
count taken of adsorption of thiosulfate.

1917 LUPPO-CRAMER: "Zum auswaschen der Fixier-losungen" ("On the Wash-
ing Out of Fixing Solutions"), Phot. 2nd. (1917), p. 686. An acid fixing
bath (non-hardening) washed out much more slowly than a plain fixing
bath.

1917 WARWICK, A. W.: "Scientific Washing of Negatives and Prints," Amer.
Phot., XI (1917), p. 317. Negative materials should be washed so that
the hypo content is reduced to at least 0.001 mg per sq-in at which con-

66 CRABTREE, EATON, AND MUEHLER [j. s. M. P. E.

centration there is no effect on the image. A mathematical treatment of
washing is given.

1917 "The Workroom (Washing)," Phot. J. of Amer., 54 (1917), p. 231. It is
claimed that a number of soakings and frequent changes are more ef-
fective than the use of running water for the elimination of hypo.

1923 DECK, N. C.: "The Permanence of Photographic Prints as Tested by
Tropical Climates," Aus. Photo-Review, 30 (1923), p. 15. Washing prints
is insufficient protection against fading when the prints are improperly
fixed.

1923 CHARRIOU, DEM. ANDRE: "Adsorption de I'hyposulfite de sodium par les
papiers photographiques" ("The Adsorption of Sodium Thiosulfate by
Photographic Papers"), Compt. rend., 177 (1923), p. 482. It is impossible
to remove all of the hypo in paper by washing because the last traces are
adsorbed. The elimination is much more rapid and complete when
washing the prints with solutions of alkali carbonates or phosphates.

1924 HICKMAN, K. C. D., AND SPENCER, D. A. : "The Washing of Photographic
Products, Parts 3, 4, and 5," Phot. J., 64, NS48 (1924), p. 539. The
water changing capacity of the apparatus is of much greater importance
than the nature of the plates. Potassium alum, when used in a 5 per cent
solution prior to fixing, retards the washing out of an "electrolyte:" Cf.
SPENCER, D. A., Phot. J., 53 (1929), p. 317, where this is further discussed
but the electrolyte not identified. However, when used in Kodak acid
fixing bath there was no difficulty in removing hypo or electrolyte. (Note:
The Kodak acid fixing bath at that time, containing alum, probably also
contained a hydroxy acid which impaired the hardening properties and
did not cause mordanting.)

1924 LUMIERE, A., AND L., AND SEYEWETZ, A. : "A propos du fixage des plaques
photographiques, limite d'emploi des bains fixateurs" ("The Limit of Use-
fulness of Fixing Baths for Photographic Plates"), Bull. soc. franq. Phot.,
11 (1924), p. 66. Baths containing 2 per cent silver bromide will not
completely remove silver salts from an emulsion. See Photographe, 65
(March, 1924).

1924 CLERC, L. P.: "Observations sur la Note deM. Charriou reproduite au
Bulletin date de decembre 1923" ("Observations on the Note of Mr.
Charriou"), Bull, soc. franc,, phot., 11 (1924), p. 84. Tests of Mr. Charriou
did not take into account the various factors known to influence the ef-
ficacy of washing. The errors due to these omissions probably exceed the
differences included in removing hypo from prints treated with pure
water and solutions of sodium bicarbonate.

1925 HICKMAN, K. C. D., AND SPENCER, D. A. : "The Washing of Photographic
Products— Part 6, The Washing of Bromide Prints," Phot. J., 65, NS49
(1925), p. 443. The removal of thiosulfate from papers is not exponential
apparently because of retention by the paper fibers.

1925 HICKMAN, K. C. D.: "Washing Motion Picture Film," Trans. Soc. Mot.
Pict. Eng., 23 (January, 1925), p. 62. Hypo removal from motion pic-
ture film was shown to be an exponential process.

1925 AMOR, A. E.: "Hypo Elimination," Brit. J. Phot., 72 (1925), p. 18. Con-

July, 1943] REMOVAL OF HYPO AND SILVER SALTS 67

eluded that washing in running water is more rapid and efficient than
washing by changes with or without the use of an eliminator.
1926 STRAUSS, P.: "Ueber die Ausmitzungsgrenze des Fixierbades" ("The
Limit of Usefulness of Fixing Baths"), Atelier, 33 (1926), p. 63. The
time of fixing should be extended as long as possible for "good bathing is
good washing." Dilute potassium iodide solution was recommended
for testing the exhaustion point of the bath.

1928 CONNER, E.: "When Is a Plate Fixed?" Bull. Phot., 43 (1928), p. 778.
A plate is thoroughly fixed when the milkiness disappears and no silver
remains in the gelatin film after washing thoroughly.

1929 SPENCER, D. A. : "Rate of Washing," Phot. J., 53 (1929), p. 317. Wash-
ing anomalies resulting from potassium alum hardening are discussed.
An unidentified but difficultly removed component was present when
the film was hardened with potassium alum.

1929 GARRIGA, R.: "Limit of Use of Fixing Baths," El. prog, jot., 10 (1929),
p. 61. Recommended that 10 cc of a 4 per cent potassium iodide be added
to 100 cc of fixing bath to determine if it is exhausted.

1931 MACONOCHIE, A. A.: "The Why and How of Washing Negatives and
Prints," Brit. J. Phot., 78 (1931), p. 241. For most efficient washing,
rapid renewal of the water at the film surface is necessary.

1931 JUDGE, A. W.: "Efficient Plate and Print Washing," Amer. Phot., 25
(1931), p. 20. Washing is effective only after all silver salts have been
removed in the fixation process.

1935 WEYDE, E. : "On the Possibility of Improving the Permanence of Photo-
graphic Prints," Brit. J. Phot., 82 (1935), p. 376. See also Photo Woche,
25 (1935), p. 474. A bath of 1 per cent sodium carbonate used after
fixing facilitates the removal of hypo by washing with water.

1937 LAZENBY, P.: "Fixing and Washing," Min. Camera World, I (1937),
p. 633. Acid hypo (non-hardening) is more difficult to remove from paper
than plain hypo.

1937 "Analecta — Testing Exhausted Fixing Baths," Brit. J. Phot., 84 (1937),
p. 104; also Phot. Rund., 74 (1937), p. 33. Add 3 or 4 drops of 10 per
cent potassium iodide to 20 cc of fixing bath. An insoluble yellow pre-
cipitate indicates the bath to be exhausted.

1938 SHEPPARD, S. E., AND HOUCK, R. C.: "The Influence of pH. on Washing
Films after Processing," J. Soc. Mot. Pict. Eng. XXXI (July, 1938), p. 67.
With an acid fixing and hardening bath and washing at the iso-electric
point of gelatin the time required to remove hypo is greater than at pH. = 7
to 8. With a non-hardening acid fixing bath there was little difference in
the washing times.

1938 SHAW, W. B.: "Toning by Used Hypo," Brit. J. Phot., 85 (1938), p. 159.
Although hypo may be readily washed out of a gelatin film by water,
the silver thiosulfate complexes formed during the fixing process can not be
wholly washed out by water alone.

1940 CRABTREE, J. I., EATON, G. T.t AND MUEHLER, L. E. : "The Elimination
of Hypo from Photographic Images," J. Phot. Soc. of Amer., VI (1940), p. 6.
Kodak Research Laboratories Communication No. 780. Under ideal con-
ditions of water renewal, the two most important factors which affect the

68 CRABTREE, EATON, AND MUEHLER

rate of washing are (7) the temperature of the wash water, and (2) the
composition of the fixing bath. The rate of removal increased with in-
creased temperature and when non-hardening fixing baths were used in-
stead of hardening fixing baths. Chrome alum hardening fixing baths
increased the rate of washing as compared with potassium alum baths.
The necessity for the elimination of hypo in prints to a low limit is shown
and the development of an efficient peroxide-ammonia eliminator for
prints is described.

1941 DURHAM, H. E.: "Hypo Eliminators," Brit. J. Phot., 88 (1941), p. 135.
It is claimed that a too rapid change of water in the early stages of wash-
ing is likely to cause the deposition of an insoluble silver-sodium thiosul-
fate complex.

1920-1941 "Letters to the Editor," Brit. J. Phot., 67-88 (1920-1941). The
complex silver thiosulfates were considered to be the major cause of the
impermanence of negatives and prints. Invariably a second fixing bath
was considered essential to eliminate the complexes. The removal of the
last traces of hypo by washing was not considered in these discussions.

EFFECT OF HIGH-INTENSITY ARCS UPON 35-MM FILM

PROJECTION*

E. K. CARVER, R. H. TALBOT, AND H. A. LOOMIS**

Summary. — In the study of the effects of high-temperature arcs on 35-mm motion
picture projection, it was noticed that the sharpness of the image on the screen was
' materially affected by changes in the heat intensity. This indicated that film does
not always lie in a flat plane in a projector gate but takes different positions at dif-
ferent lemperatures. In order to study this phenomenon more carefully, a portion of
the projector gate was cut away permitting high-speed Cine Kodak pictures (about
1500 frames /second) to be taken of the film as it passed by the aperture of a projector.
The pictures show that most films enter the gate in a state of slight positive curl (curl
toward the emulsion) and then change to a state of negative curl during the instant
they remain exposed to the heat of the arc. This change in curl is due to the expansion
of the emulsion layer by the heat. This effect is especially pronounced with the new
high-intensity arcs.

The effect on the quality of the screen image of this change in curl of the film in the
gate was studied by means of high-speed Cine Kodak analysis of the screen image.
The pictures show that at high heat intensities and with the projector focused to give
the sharpest image on the screen, the images are in sharp focus for only a portion of
their duration on the screen. Each screen image comes into view out of focus and
gradually becomes sharper until just before the pull-down when it reaches its maximum
sharpness. Such pictures are of good screen quality if the projector is focused care-
fully.

Under certain conditions, when the film is in a very moist state and when lamps of
the highest heat intensity are used, the screen images may not all be sharp. Occasion-
ally a few frames may be entirely out of focus. The high-speed analysis of the action
of the film in the gate shows that these out-of-focus frames behave in an abnormal
manner. In these frames the normal change in curl from positive to negative in the
gate is interrupted by a reversal back to positive curl. Thus at the end of the pull-down
cycle these frames lie in a plane slightly toward the lens of the projector, whereas all of
the normal frames lie in a plane slightly toward the lamp from the plane of the gate.
The distance between these two planes is greater than the depth of focus of the lens and
thus these abnormal frames appear out of focus. It is believed that this sudden re-
versal to positive curl is due to a contraction of the gelatin due to loss of moisture.

We recommend that the heat intensity at the aperture, as measured by a thermo-
couple which we have described, should not exceed 1250°F and that films should be
dried thoroughly.

* Presented at the 1942 Fall Meeting at New York, N. Y.
** Eastman Kodak Company, Rochester, N. Y.

70 CARVER, TALBOT, AND LOOMIS [J. S. M. P. E.

Recent improvements in arc lamps and carbons which have
made possible brighter pictures on the screen have brought forward
again the problem of the effect of extreme heat on motion picture
film.

Whereas in the past a thermocouple held in the gate of a projector
seldom reached a temperature of 1000°F, some of the arcs and lamps
now in use may heat the thermocouple to as high as 1700 °F. These
excessively high temperatures are not without effect upon the physical
state of the film subjected to them and consequently on the resulting
picture quality.*

The purpose of this paper is to illustrate the physical changes
that take place in the film during the brief time it remains stationary
in the gate of the projector and is subjected to these high tempera-
tures, as well as the effect that these phenomena have upon the
appearance of the screen images.

Shift of Focus with Changes in Arc Intensity. — Changes in the heat
intensity at the aperture were measured by inserting a thermocouple
at the center of the aperture in the exact plane normally occupied by
the film. An iron -constan tan thermocouple terminating in a stain-
less steel disk 6 mm in diameter was employed. The temperature
which this thermocouple will attain is arbitrarily called "heat in-
tensity." This manner of estimating heat intensities is admittedly
empirical, and is influenced by the size and color of the disk, radiation
therefrom, etc., but furnishes quite reproducible results.

It was noticed immediately that the sharpness of the picture
upon the screen was influenced materially by the heat intensity.
A picture whose image was in sharp focus with a heat intensity of
1000°F could be thrown decidedly out of focus if the heat intensity
were raised or lowered a few hundred degrees. This indicated that
film does not always lie in the same plane in the gate but takes
different positions at different temperatures. In order to demon-
strate this more clearly and at the same time obtain a measure of these
displacements, it was necessary to calibrate the projector lens system

* The original title of this paper was, "Effect of High Gate Temperatures upon
35-Mm. Film Projection," The use of the expression, "gate temperatures," was
criticized severely (and correctly) because of the fact that the gate itself does not
have a high temperature. The gate is merely a pathway through which the in-
tense radiant heat travels. The thing of importance is the intensity of this heat
flux and not the temperature of the air within the gate, which, of course, is
approximately room temperature. The new title, therefore, describes more ac-
curately the effects to be discussed.

July, 1943]

EFFECT OF HIGH-INTENSITY ARCS

so that axial displacement of the center of the film in the aperture
could be followed by noting the distance the lens must be moved
from its normal position to keep the image in sharp focus upon the
screen.

Study of Film Movement in Aperture by Focusing Method. — The
lens system was calibrated by attaching an indicator to the system
as shown in Fig. 1. The lower part of the indicator hand is attached

FIG. 1. Focus indicator on E-7 projector.

directly to the lens barrel, then to a fixed fulcrum which magnifies
the lens displacement at the tip of the pointer so that lens move-
ments of 0.01 inch are read plainly and movements of the order of
0.0025 inch can be estimated. '

The focus indicator was calibrated in the following manner: A
strip of film was held in a perfectly flat position in the gate by means
of a piece of steel 35 mm in width. A small hole drilled in the center
of this metal strip allowed a portion of the test image to be projected
upon the screen. Since the film was not in motion a faint source of
light was used at a considerable distance from the film in order to

CARVER, TALBOT, AND LOOMIS

[J. S. M. P. E.

eliminate any heat effect. Thus the lens setting for best visual focus
for perfectly flat film in the gate was established. This we shall call
"zero focus." In a like manner, the lens setting for film that has-
been displaced a known amount was obtained by mounting the film
on metal shims of known thickness and placing the shims against the

FIG. 2. E-7 gate cut away for aperture
pictures.

film trap. Thus if a shim 0.01 inch in thickness were used, the film
would be moved axially toward the lens 0.01 inch. The best visual
focus was again obtained by projection of the image and the focus
indicator calibrated. As is well known, film that curls so that the emul-
sion side is concave is referred to as having "positive curl," and film
that curls in the opposite direction is referred to as having "negative
curl." Since the film in the gate has its emulsion side toward the arc,

July, 1943]

EFFECT OF HIGH- INTENSITY ARCS

and has its edges pressed against the gate, it will be seen that if film
has positive curl, the image plane at the center of the film will be
shifted toward the lens of the projector. The shift of the lens in
order to correct for this displacement will be referred to as a positive
focus. In like manner, if the film in the gate of the projector has a

FIG. 3. E-7 gate with reference bar at-
tached.

negative curl, the image plane at the center of the film will be dis-
placed in the opposite direction or toward the lamp. The shift of
the lens to correct for this displacement will be referred to as a
negative focus. Thus it may be seen that the effective position of the
film in the gate, so far as the screen image is concerned, may be
arrived at during projection simply by setting the lens at the best

CARVER, TALBOT, AND LOOMIS

[J. S. M. p. E.

visible focus and reading the displacement of the lens in bundredths
of an inch on the dial.

It was discovered immediately that almost without exception new
films projected at the customary heat intensity of about 850 °F or
higher assumed a negative curl in the aperture. This was viewed
at first as a rather disconcerting discovery inasmuch as such films are

FIG. 4. Cut-away E-7 gate on projector.

almost always in a state of slight positive curl. In fact, film entering
and leaving the gate was observed to have slight positive curl, and
yet the focus indicator showed plainly that the film in the aperture,
while the image was being projected upon the screen, was negative
in curl to the extent of, in many cases, at least 0.01 inch. On the
other hand, it is quite logical to assume that temperatures of this
magnitude, even though operating but for an instant, could effect
this change in the physical state of the film. One has, in effect, a
situation analogous to a bimetallic strip such as is used in many

July, 1943] EFFECT OF HIGH-INTENSITY ARCS 75

thermostats. This consists of two bonded metal strips, one having
a greater coefficient of expansion than the other. When heated, the
strip is forced to assume a curvature convex to the more rapidly ex-
panding element. In our case, the emulsion layer and the support
form the two members of the strip. The expansion takes place al-
most wholly in the emulsion layer since the support absorbs practi-

FIG. 5. High-speed Cine Kodak focused on aperture.

cally none of the heat. Expansion of the emulsion layer would force
the strip of film to be convex to the emulsion or negative in curl.

Study of Film Travel in Aperture by High-Speed Camera Analysis
"Negative Drift." — In order to determine at what point in the pull-
down cycle the reversal of curl took place, high-speed motion pictures
were taken of the film as it passed through the aperture. In most of
this work, a Simplex E-7 projector with a McAuley Hy- Candescent
Lamp and New Super H.I. National carbons was used. However,

CARVER, TALBOT, AND LOOMIS [J. S. M. P. E.

SHADOW OF THE
PULL-DOWN BLADE

16 PICTURES

SHADOW OF THE

FLICKER BLADE

12 FRAMES

certain phases of the work were repeated with other projectors and

other lamps and the same results were obtained.

It was necessary to cut away a
portion of the E-7 gate, as shown in
Fig. 2, in order to obtain the pic-
tures of the film as it passed by
the aperture. A reference bar was
attached to the gate so that slight
movements of the film in rela-
tion to this bar could be observed.
(See Fig. 3.)

Fig. 4 shows this special gate in
place on the projector and Fig. 5
shows the high-speed Cine Kodak
in position to take the pictures.
The pictures were taken at an
angle of about 15 degrees from the
plane of the film.

By this means pictures have
been taken of film in the aperture
of projectors at a rate of about
1500 frames per second. In other
words, with film traveling through
the 35-mm projector at the nor-
mal rate of 24 frames per sec-
ond and with the film remaining
stationary in the aperture for y32
second, about sixty 16-mm ex-
posures were made between suc-
cessive pull-downs. As is known,
there are two blades on the shut-
ter of a standard 35-mm projector.
One blade is to mask the movement
of the film as it comes into place
in the aperture, and the purpose
of the other blade is to interrupt the
light once during projection so as
to keep the periods of dark and

light on the screen of more equal duration and thus minimize flicker.

Therefore, the 16-mm high-speed pictures have a dark portion of

16 PICTURES

SHADOW OF THE
PULL-DOWN BLADE

FIG. 6. High-speed pictures of
35-mm film in the aperture. The
pictures represent the interval from
the end of one pull-down to the
start of the next pull-down.

July, 1943]

EFFECT OF HIGH-INTENSITY ARCS

about 12 frames between consecutive pull-downs of the 35-mm film,
representing the blocking-out of the light by the flicker blade. A
typical sequence of pictures obtained from the end of one pull-down
to the beginning of the next is shown in Fig. 6.

When the 16-mm pictures were projected the movement of the
35-mm film in the aperture of the projector could be clearly seen.

FIG. 7. Enlargement of four frames from film shown in Fig. 6.

(1) Immediately after the pull-down.

(2) Immediately before the flicker blade.

(3) Just after the nicker blade.

(4) Just prior to the next pull-down.

The pictures show that the film comes into the aperture in its nor-
mal state, i. e., flat or slightly positive in curl; then as the heat strikes
the film the emulsion layer expands, forcing the film into a state of
negative curl. The expansion of the film starts immediately after
the pull-down and reaches its maximum just before the next pull-
down. The passing of the flicker blade halts this expansion effect
momentarily.

Fig. 7 is an illustration of four 16-mm frames taken of one com-
plete 35-mm pull-down cycle. No. 1 frame was taken immediately

78 CARVER, TALBOT, AND LOOMIS [J. S. M. P. E.

after the pull-down; No. 2 frame immediately before the flicker
blade; No. 3 frame just after the flicker blade; and No. 4 frame
just prior to the next pull-down. In the pictures the reference bar
can be seen protruding into the aperture. The movement of the
film can be noticed by observing the position of the numbers in rela-
tion to the reference bar at different portions of the pull-down cycle.
In the No. 1 frame, the third column of figures from the left is masked
completely by the reference bar; in No. 2 frame, this column of

FIG. 8. Scene used for high-speed screen pictures. The encircled portion

is the target.

figures has moved out almost into view. In No. 3 frame, the film
appears to be in about the same position as in No. 2 frame. This is
due to the hesitation or even slight retraction of this heat-expansion
effect as the flicker blade passes between the light and the film. In
No. 4 frame, the third column of numbers is in full view.

The lateral displacement or change of curl produced by the ab-
sorption of heat in the emulsion layer is a normal phenomenon, and
takes place with all types of film, i. e., it is the same for fine-grain
positive as for the older type of positive, and it takes place to an
equal extent in all manufacturers' films that have been tested. It is

July, 1943] EFFECT OF HIGH- INTENSITY ARCS 79

dependent upon the heat intensity and the density of the image;
the higher the heat intensity, the greater is the displacement. Like-
wise, the greater the density, the greater is the displacement, since
more heat is absorbed. Strange as it may seem, the displacement is
independent of the natural curl of the film — a film having a high
positive curl will be displaced to the same extent as a film with little
or no curl.

Effect of ''Negative Drift" on the Appearance of the Screen Image. —
It will be of interest now to examine what effect this "negative drift,"

FIG. 9. Enlargement of target.

as it is frequently referred to, has upon the quality of the screen
image. In order to demonstrate this, the high-speed camera with a
telephoto lens was focused upon a portion of the screen image, as
shown in Fig. 8. The portion of the screen image encircled in the
above figure consists of a focusing chart, an enlargement of which
appears in Fig. 9. The projector was focused to produce a sharp
image upon the screen. As stated before, this required that the lens
be focused upon a plane 0.01 inch toward the lamp from the aperture.
The images appeared sharp to an observer a few feet from the screen.
There was, of course, some lack of definition due to the extreme
magnification. When the 16-mm high-speed pictures were pro-
jected, it was seen that for each pull-down cycle the 35-mm screen

80 CARVER, TALBOT, AND LOOMIS [J. S. M. P. E.

image was out of focus when it first came into view. It then became
sharper and sharper until, after the flicker blade and just prior to
the next pull-down, the image was in sharp focus. A series of four
frames taken from this 16-mm high-speed film is shown in Fig. 10.

FIG. 10. Enlargement of four individual frames from high-speed screen

pictures.

(1) Immediately after the pull-down.
(2} Immediately before the flicker blade.
(5) Just after the flicker blade.
(4) Just prior to the next pull-down.

As before, the four frames represent different portions of the pull-
down cycle. No. 1 frame was taken immediately after the pull-
down; No. 2 frame immediately before the flicker blade; No. 3
frame just after the flicker blade; and No. 4 frame just prior to the
next pull-down.

The appearance of the screen image with different focus settings
of the projector lens was tested using a set-up as shown in Fig. 11.

July, 1943]

EFFECT OF HIGH- INTENSITY ARCS

A cord was wound about the focusing knob of the projector lens and
attached to an indicator on the screen in such a manner that the
exact focal setting of the projector lens appears in the 16-mm pictures
of the 35-mm screen image. In operation the projector is started
and the image thrown on the screen with the projector lens focused
+0.02 inch. The high-speed camera is started and as soon as it has
attained maximum speed, the focus of the projector lens is gradually
changed to a focus of —0.02 inch, the movement being recorded by
the indicator on the screen.

FIG. 11. Set-up for recording the setting of the 35-mm projector
lens on the high-speed pictures of the screen image.

With the projector focused on the positive or lens side of the aper-
ture, the image is in sharp focus only immediately after the pull-
down, since at this point it is nearest to the plane on which the pro-
jector lens is focused. As the film in the aperture drifts away from
this original position or toward the negative plane nearer the arc
lamp, the film moves beyond the depth of focus of the lens and the
image appears out of focus. A series of four frames taken from this
portion of the film is shown in Fig. 12. In these pictures the indi-
cator shows that the projector lens was focused at about +0.008

CARVER, TALBOT, AND LOOMIS

[J. S. M. p. E.

inch or on a plane 0.008 inch toward the lens from the aperture. As
the focus of the projector lens is changed to the negative or lamp side
of the aperture, the effect is the opposite. Here the image comes into
view out of focus and changes steadily to sharp focus. This is shown
in Fig. 13. In these pictures the indicator shows that the projector

FIG. 12. Enlargement of four individual frames from high-speed screen pic-
tures, with projector lens focused at +0.008 inch.

lens was focused at about —0.005 inch or on a plane 0.005 inch toward
the lamp from the aperture.

The reason why the projected images appear sharpest when the
projector is focused on the negative plane is not understood defi-
nitely. It is stated simply as an observation repeated many times
with various films, projectors, and operators. It may be that the
film in the aperture is in a state of rapid movement during the first
one-half or three-quarters of the pull-down cycle due to this heat

July, 1943]

EFFECT OF HIGH- INTENSITY ARCS

expansion effect. It is only after this expansion has taken place that
the film remains relatively stationary. Possibly the eye prefers to
focus upon the image during that portion of the cycle in which the
film is relatively free from motion even though this period represents
but a fraction of the entire cycle.

FIG. 13.

Enlargement of four individual frames from high-speed screen pic-
tures, with projector lens focused at —0.005 inch.

All the film which we have described has been perfectly normal.
No in-and-out of focus was observed upon the screen, and excellent
projection quality was obtained in spite of the negative drift observed
with the high-speed movies. The effect has been obtained with
film of all manufacturers and with many types of experimental film.
The effect is apparent at all heat intensities above 850 °F as mea-
sured by our thermocouple using the particular print with which we
experimented most. In spite of the fact that sharp pictures were
obtained even though this negative drift was occurring, nevertheless

84 CARVER, TALBOT, AND LOOMIS [J. S. M. P. E.

it was certainly true that the focusing had to be far more carefully
done with the high temperatures, when the negative drift was large,
than with the low temperatures, when it was absent.

The "ln-and-0ut of Focus" Phenomenon. — Up to this point the
work that has been presented might be regarded as largely of aca-
demic interest, its purpose being to contribute to our knowledge of
the normal operation of films in 35-mm projectors operating at high
heat intensities. However, much trouble of a serious nature has
been encountered in the trade with a condition that has come to be
known as the "in-and-out of focus" difficulty. In a number of
theaters, particularly in the de luxe houses, it has been impossible at
times to keep the image in sharp focus upon the screen. The effect
is exactly what the designation "in-and-out of focus," implies; that
is to say, the image is perfectly sharp the greater part of the time but
occasionally goes out of focus momentarily. Usually the first few
projections of prints subject to this difficulty are normal. After
four or five projections or thereabouts, and for several succeeding
projections, it may become difficult, if not impossible, to keep the
picture in sharp focus.

It was some time after this difficulty was encountered before the
mechanism by which it took place was discovered. Since it occurred
most frequently with high-intensity arc projectors which often em-
boss the film, many believed that the focusing difficulties were asso-
ciated with this embossing. However, it is a matter of record that
the difficulty may occur in the initial projection of a print on which
there is no embossing or distortion of any kind. Likewise this in-
and-out of focus difficulty disappears with repeated projections dur-
ing which time the embossing of the film increases gradually.

Again it was by high-speed analysis of film movements in the
aperture that the true cause of the difficulty was discovered. We
were able eventually to obtain high-speed pictures of film in the gate
of a projector at the exact instant the picture was seen to go out of
focus on the screen. The difficulty of obtaining such pictures may
be realized by considering that even during bad in-and-out of focus
trouble only relatively few frames of an entire roll exhibit the defect
and it is impossible to tell beforehand when the trouble is about to
occur. The time required to expose 100 feet of film in a high-speed
camera is about 3 seconds, and once the camera is started the entire
roll must be run off. Therefore, most of our shots show the action
of perfectly normal film. High-speed aperture pictures of film sub-

July, 1943] EFFECT OF HIGH- INTENSITY ARCS 85

ject to this difficulty show that the great majority of frames behave
in a normal manner, i. e., enter the gate in a state of slightly positive
curl and expand to a state of negative curl. The projector is, there-
fore, focused on this negative plane. Suddenly, however, a few
frames come into position in the normal manner, start to expand,
and then, before reaching the plane of critical focus, jump back again
into a state of positive curl. These frames, because of their position
at the end of the cycle, are outside the plane of sharp focus of the
projector lens, and their images are therefore more or less completely
out of focus on the screen.

In order to determine what factors caused certain films to behave
in this manner, the variables of processing and projection were
studied that were thought to have any bearing on the subject. Of
the various processing variables, only one was found to have any
influence on the in-and-out of focus effect — the amount of moisture
left in the film after drying. If the film is not dried sufficiently the
in-and-out of focus effect is increased greatly. This and other ob-
servations have led us to believe that the sudden shift in curl of the
frames that appear out of focus is due to a drying-out of the emulsion
under the influence of the high heat intensity in the aperture. It is
believed that the reason why insufficiently dried films exhibit the
in-and-out of focus defect is that (1) there is more moisture in the
emulsion, which therefore contracts more on losing this moisture, and
(2} the moisture tends to make the film base softer at high tempera-
ture, thereby offering less resistance to the pull of the emulsion than
if the film base were drier. These effects, due to insufficient drying,
formerly caused some real difficulty with the use of certain fine-grain
films. These emulsions reached the point of sensible dryness in the
drying cabinet in about one-third the time required for the older
type of film. As a consequence some of the laboratories used milder
drying conditions for the fine-grain film in order to cause it to dry
in the same position in the cabinet as the type previously used. Thus,
even though the emulsion appeared dry there was certainly more
moisture both in the emulsion layer, and particularly in the support,
than in the case of films dried under the older conditions. Upon
correcting these drying conditions much of the in-and-out of focus
difficulty disappeared.

The various factors in the projection of film that might influence
the in-and-out of focus effect on the screen were also studied. These
were found to be the characteristics of the lens, the angle of pro-

CARVER, TALBOT, AND LOOMIS

[J. S. M. P. E.

jection, and the heat intensity. In general, the more critical the
lens, the more carefully it must be focused. Thus an //2.0 coated
lens gives a picture of superb quality if the lens is focused with ex-
treme care, but the depth of focus is so small that a slight misad-
justment of the lens causes small movements of the film in the aper-
ture to be noticeable on the screen. Likewise a steep angle of pro-
jection produces the same effect as decreasing the depth of focus of
the lens.

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FIG. 14. Effect of Aklo heat-absorbing filter on the heat inten-
sity at the aperture of a 35-mm projector and on the light intensity at
the screen. The "aperture temperatures" are the temperatures
reached by the thermocouples when placed at the center of the aper-
ture. The per cent light distribution indicates the ratio of the illu-
mination at a point 5 per cent of the screen width from the edge of the
screen to the illumination at the center of the screen.

The third factor, the heat intensity, was found to be of great im-
portance. It has been observed many times that films exhibiting the
in-and-out of focus effect upon the screen at heat intensities of 1700 °F
would project satisfactorily if the heat intensities were reduced to
1250°F. High heat intensities cause the expansion and contraction
forces operating on the emulsion to be more violent in nature and, at
the same time, soften the film base so that it is less able to withstand
them.

One obvious method of reducing the heat intensities of these high-
intensity lamps is to insert a heat-absorbing filter between the lamp
and the projector. Fig. 14 shows the reduction of heat and

July, 1943] EFFECT OF HIGH- INTENSITY ARCS 87

effected by this procedure. The abscissa values correspond to the
various positions of the condenser lens. The low numbers refer to a
position close to the arc, thus giving a large spot and consequently
low heat intensity and light values. At the point of maximum heat
and light or at a condenser setting of about No. 6, the insertion of
the heat-absorbing filter has effected a 23.5 per cent reduction in heat
intensity with a reduction of but 14 per cent in light at the center of
the screen.

As the result of this work, we feel justified in making two recom-
mendations to the trade : , one concerning heat intensities and the
other dealing with the drying of film. It is recommended that the
heat intensity at the aperture of a projector be kept down to ap-
proximately 1250°F by the use of heat-absorbing glass* or other
means. It is recommended also that processing laboratories dry
their films more thoroughly, taking into consideration the fact that
the film base must be dried as well as the emulsion. It should be
pointed out, however, that under certain conditions overdrying of
films may result in "spoky" rolls, a defect that is discussed in the
paper, "Film Distortions and Their Effect upon Projection Quality."1

Acknowledgment. — In conclusion, we wish to give full acknowl-
edgment to Mr. Eldon E. Moyer for the time and skill expended
in taking these high-speed motion pictures, and to Dr. Alfred C.
Robertson and Dr. Geoffrey Broughton for many suggestions con-
tributed to the work.

REFERENCE

1 CARVER, E. K., TALBOT, R. H., AND LOOMIS, H. A.: "Film Distortions and
Their Effect upon Projection Quality," /. Soc. Mot. Pict. Eng., XLI (July, 1943),
p. 88.

* A piece of Corning 'Extra Light Shade Aklo heat-absorbing glass 4x/4 inches
in diameter and 1.2 mm thick was used in place of the Pyrex glass normally found
between the lamp house and the mechanism of the E-7 projector. To minimize
breakage, the glass was cut into five strips about 7/8 inch wide.

FILM DISTORTIONS AND THEIR EFFECT UPON
PROJECTION QUALITY*

E. K. CARVER, R. H. TALBOT, AND H. A. LOOMIS**

Summary — The five most generally recognized types of film distortion are dis-
cussed. These consist of curl, spokiness, embossing, flute or long edges, and buckle
or short edges.

Curl has come to be an accepted fact and is ordinarily without importance in pro-
jection except when it becomes excessive.

Spokiness, sometimes called square rolls or hexagonal rolls, is a phenomenon ob-
served when film with a high degree of curl is wound with insufficient tension to
keep the roll perfectly round. Poor screen quality in the case of 16-mm films has some-
times been associated with this defect.

Embossing is due to differential shrinkage or hardening of the emulsion caused by
local absorption of heat in the dense portion of the picture. Careful tests have failed
to show any effect upon the screen such as in-and-out of focus due to image embossing.
Measurements of the magnitudes of the distortions show that these are ordinarily
much less than the depth of focus of the lens.

Flute, or long edges, is more often seen with safety film than with nitrate film. It
is generally caused by a stretching of the edges by recessed rolls, by shrinking the center
of the film with high-temperature arcs on projection, or by exposing the roll to exces-
sively high humidities, which -causes swelling at the edges ~ Laboratory tests as well
as field experience indicate that fluted edges very rarely cause distortion of the images
on the screen.

Buckle, or short edges, is believed to be the most serious type of film distortion.
It is caused by greater loss of moisture or solvent from the edges of the film than from
the center. This leaves a fullness of the center resulting in an "oil-can" effect when
film passes through the projector, thus producing pictures that go in-and-out of focus
on the screen.

Buckle trouble may result from storing rolls of film in packages that are easily
permeable to moisture vapor but it may be avoided by the use of impermeable packaging
materials.

i X

There are several types of film distortion commonly observed in
processed film in the trade. Of these the most important are curl,
spokiness, embossing, flute or long edges, and buckle or short edges.
They are all caused by expansion or contraction, stretching or shrink-
age, of certain portions of the film.

* Presented at the 1942 Fall Meeting at New York, N. Y.
** Eastman Kodak Company, Rochester, N. Y.

FILM DISTORTIONS 89

Curl. — Curl has come to be an accepted fact and is ordinarily
without importance in projection except when it becomes excessive.
It is ordinarily caused by shrinkage of the gelatin emulsion at low
humidities, when it is known as front curl, face curl, or positive curl.
When the emulsion has swelled at high humidities or the base has
shrunk, so as to make the emulsion side convex, the curl is called
back curl or negative curl.

Spokiness. — Spokiness is a phenomenon observed when film with a
high degree of curl is wound with insufficient tension to keep the roll
perfectly round. The explanation appears to be as follows: A
plane sheet of material can easily be bent or curled in one direc-

FIG. 1. (Left) smooth roll; (right) spoky roll.

tion or another, but strongly resists bending in two directions at the
same time. Thus when a strip of curly film is wound into a roll, there
is a tendency for each layer to resist bending for part of a turn and
then to bend sharply. As successive layers are wound on, each break
reinforces the last until a definite hump has been formed. There
will be a succession of these humps around the roll giving a character-
istic appearance when the roll is viewed from the side. The succes-
sive humps appear as radial lines, somewhat like the spokes of a wheel.
Such rolls are referred to as being "spoky."

Sometimes, due to the fact that the rolls appear polygonal rather
than perfectly round, they are referred to as square, octagonal, or
hexagonal rolls, regardless of the exact number of sides of the polygon.
A spoky roll is shown beside a smooth roll in Fig. 1.

90 CARVER, TALBOT, AND LOOMIS [J. S. M. P. E.

Spokiness occurs both with 35-mm and with 16-mm film but does
not appear to cause -projection difficulties with 35-mm film. With
16-mm film, possibly because there is greater tendency for the spokes
to "set" in the film, or possibly because of the lower pressure on the
gate shoes in the projectors, in-and-out of focus effects are sometimes
produced by the film distortion resulting from spokiness. Spokiness
is generally the result of overdrying in processing, resulting in film of
high positive curl, and of loose winding, which allows film of high
curl to spoke more readily. We must choose, therefore, a middle
course between overdrying and underdrying. The former may
result in focusing difficulties as a result of spokiness ; the latter may
give thermal "in-and-out of focus" effects such as described in the
paper, "Effect of High-Intensity Arcs upon 35-mm Film Projection."1

Two distinct kinds of spokiness may be observed. If curly film
is wound with the concave side out, the spokes visible on the two
sides of the film will always be opposite each other. If the roll is
wound with the concave side in, the spokes will be alternate. The
spokes seen on one side of the roll will never be opposite those on the
other side of the roll.

Embossing. — Embossing was a common defect prior to the advent
of the rear type shutter, which came into use at about the same time
as did the sound movies. It has always been considered an important
defect from the point of view of projection quality. It is obviously
due to differential heating of portions of the image due to varying
densities throughout the image. The blacker portions get hotter
and are shrunken by the heat. Sometimes this effect is most pro-
nounced at the frame lines, when it becomes known as frame-line
embossing. During the experiments discussed in the preceding
paper,1 considerable heavy embossing was produced by the extreme
arc temperatures used, but in no case was the embossing sufficient
to cause any focusing difficulties in the film. Measurements of the
actual depths of the embossing gave no values higher than 0.0003
inch, which is well within the range of the depth of focus of the pro-
jection lenses. Although it may possibly be that under certain
circumstances embossing may increase the tendency of film to show
in-and-out of focus effects, we have never found a single case of em-
bossing that by itself gave focusing difficulties. One fact was ob-
served, however, that fresh film, and especially film not thoroughly
dried, tended to emboss more than well seasoned and dried film.
Since it is also a fact that insufficient drying and seasoning tends to

July, 1943] FILM DISTORTIONS 91

produce in-and-out of focus troubles from other causes, we sometimes
find that film that has been embossed has also shown in-and-out of
focus troubles.

Flute or Long Edges. — The fourth type of film distortion, flute or
long edges, is now seen more often with safety film than with nitrate
film. A typical example of flute or long edge film is shown in Fig. 2.
It is caused by shrinking the center of the film without shrinking
the edges or, conversely, by stretching the edges.

(a) Flute from shrinkage of the center of the film: When film, es-
pecially safety film, is projected repeatedly at high heat intensities,
the center tends to shrink more than the edges, causing a particular
type of flute often known as "twist," since a strip of film stretched
between two points gives the appearance of being twisted.

FIG. 2. Flute, or long edge, in cine film.

(b) Flute from stretching the edges of the film by means of recessed
rolls: The edges of the film are often stretched in processing machines
by pulling the film too tightly over recessed rolls while the film is wet
or while it is hot.

(c) Flute from stretching the edges of the film by the use of twisted
strands: Occasionally processing machines are designed in which the
film is turned between each pair of rollers so that the emulsion side
will never be in contact with the rollers. If the distance between
the rollers is too short this twist puts an additional strain upon the
edges of the film which often produces flutes.

(d) Flute from stretching the edges of the film through swelling of the
edges: Flute is sometime produced in raw film if a tightly wound roll
is exposed to very high humidities. Moisture is absorbed by the

CARVER, TALBOT, AND LOOMIS

[J..S. M. P. E.

edges of the film but does not travel far into the center. This means
that the edges increase in thickness and each layer builds up on the
one under it. Even though this thickening of a single layer of film
may amount to only 0.00001 inch, there are, nevertheless, 650 layers
in a 1000-ft roll of film. The increased thickness of each layer builds
up on those below it so that the edges of the roll will have a diameter
0.0065 inch greater than the center and this increased diameter can
occur only by stretching the edges of the film.

FIG. 3. Buckle, or short edges, in cine film.

Buckle or Short Edges. — The kind of distortion that has caused by
far the greatest amount of trouble with 35-mm film is short edges.
At the Eastman Company the term "buckle" is reserved entirely for
this type of distortion, although in the trade almost any type of dis-
tortion is frequently referred to as "buckle." Fig. 3 shows a typical
example of buckle produced by short edges. It is ordinarily pro-
duced whenever a film containing a sufficient amount of water or
residual solvent is wound tightly and permitted to dry so rapidly
that the moisture can not diffuse from the center toward the edges
as rapidly as it is taken away from the edges. The edges shrink as

July, 1943] FILM DISTORTIONS 93

they dry and may become permanently distorted. The effect is
worse with film having a high potential shrinkage than with modern
low shrink film, but even this film can be buckled due to moisture
losses alone if conditions are right.

The use of ordinary cardboard boxes caused by the shortage of tin
for shipping film from laboratories to exchanges offers ideal condi-
tions for the formation of buckle. The freshly processed film, often
in equilibrium with 50-60 per cent relative humidity, often may be
exposed to humidities as low as 10-15 per cent due to the high mois-
ture permeability of the cardboard. Experiments have shown
that conditions such as described above will almost invariably buckle
moist film, whereas film that has been thoroughly dried in processing
will not buckle as readily. If the film, before being placed in plain
cardboard containers, is wrapped in an envelope of a highly moisture-
resistant paper, this tendency to buckle is practically eliminated.
New types of cardboard boxes in which a highly moisture-resistant
layer is incorporated in the box itself will probably protect the film
even better than these moisture-proof envelopes.

The reason why short edges are so much more likely to produce in-
and-out of focus effects upon the screen than any other kind of film
distortion is that these short edges always leave a fullness in the
center of the film that produces an "oil-can" effect. The center of
the film is free to bend in one direction or the other. It is this un-
certainty as to the direction in which it will bend that leads to the in-
and-out of focus effect upon the screen. Film showing in-and-out of
focus due to this particular effect can sometimes be corrected by
changing the moisture content of the film so as to give it a potential
tendency to curl in either one direction or the other. As long as it
always curls in the same direction while it is in the gate, no in-and-
out of focus will be observed. Such film can further be corrected by
stretching the edges. This can be done by passing the film over an
internally heated flat roller which shrinks the center and stretches
the edges slightly.

It is our hope that this discussion will not only help to clarify the
nomenclature of different types of film distortions, but that by help-
ing us to understand the causes of these distortions, will result in
better projection and better entertainment.

REFERENCE

1 CARVER, E. K., TALBOT, R. H., AND LOOMIS, H. A.: "Effect of High-Intensity
Arcs upon 35-Mm Film Projection," /. Soc. Mot. Pict. Eng., XLI (July, 1943), p. 69.

CARBON ARC PROJECTION OF 16-MM FILM*

W. C.KALB**

Summary. — Characteristics of the high-intensity arc as applied to the projection
of 16-mm film are described. Carbon trim, quality of light, magnification, optical
speed, power of the projection lamp, and the intensity and distribution of the screen
light are also discussed.

Projection of 16-mm film has passed beyond the limitations of the
living room and the small classroom. It is now shown before groups
of such size that enlargement to a screen image several feet in width
is essential to satisfactory presentation. This has created the need
for a large volume of projection light to provide the recommended
level of screen brightness, a need that has been met in a highly satis-
factory manner by the adaptation of the high-intensity carbon arc
to 16-mm projection.

HIGH-INTENSITY PROJECTION LAMP

The projection lamp developed for this purpose1 is a direct-current
lamp operated through a rectifier from a 110- volt, single-phase, a-c
supply, with a current demand of less than 15 amperes from the
supply line. The 6-mm X 8-inch positive carbon and 5.6-mm X
6-inch negative2 are designed to operate at 30 amperes d-c with 28
volts across the arc. The burning life of this trim is approximately
one hour, ample for the projection of a 2000-ft, 16-mm reel at sound
speed of 24 frames per second.

Fig. 1 shows the spectral energy distribution of the light from this
arc. The composition of the positive carbon core is somewhat differ-
ent from that of high-intensity positives used for 35-mm projection,
increasing the proportion of light emission at longer wavelengths.

* Presented at the 1942 Fall Meeting at New York, N. Y.
** National Carbon Company, Cleveland, Ohio.

CARBON ARC PROJECTION

This modification is made to adapt the color-quality of the light to
color-film processed for projection by incandescent light, which is
customary in the production of 16-mm color-film. Color-temperature
of the screen light is approximately 4450 °K, giving excellent color
reproduction.

The lamp mirror is designed to focus the arc crater image at the
film aperture with a magnification of 4x/2 : 1 which effectively covers
the aperture. The beam divergence is sufficient to fill the 2-inch,
//1. 6 lens extensively used for 16-mm projection.

VIOLET BLUE GREEN YELLOW ORANGE

RED

4000

5000 6000

WAVE LENGTH IN ANGSTROM UNITS

7000

FIG. 1. Spectral energy distribution of light projected
on screen from the high-intensity carbon arc developed
for 16-mm projection.

SCREEN LIGHT

This high-intensity arc lamp, operated with a 2-inch, //1. 6 lens but
without shutter, film, or heat filter, projects 2300 lumens to the
screen. A representative figure for shutter transmission on commer-
cial types of 16-mm projectors is 60 per cent, and 80 per cent is a
representative transmission factor for the type of heat-filter used on
16-mm carbon arc projectors. The screen light available with an
//1. 6 lens, shutter running and filter in place, is therefore about 1100
lumens. This is obtained with 80 per cent side- to-center distribution
of screen brightness, which is about the optimum of good projection
practice. The corresponding screen illumination with other lenses,
calculated on the basis of relative / values, is about 700 lumens with

96 W. C. KALB [j. s. M. p. E.

an //2.0 lens and, with an //2.8 lens, about 360 lumens. Some pro-
jectors have no heat-filter but use a rear shutter, or blower, or a
combination of the two, to maintain low film temperature. With
this construction somewhat greater screen illumination may be ex-
pected, other factors being equal.

Calculated values are given in Table I showing, for various widths
of screen image, the brightness in foot-lamberts at the center of the
screen obtained under the stated conditions with high-intensity
carbon arc projection. The figures given above for screen illumina-
tion are used as the basis for this table, assuming 80 per cent side-
to-center distribution of the light on the screen.

TABLE I

Foot-Lamberts at Center of Screen Image of Specified Width

Matte surface screen of 75% reflectivity
Shutter running — transmission 60 per cent
Heat-filter of 80 per cent light transmission
No film in projector

Width of
Screen Image Foot-Lamberts at Center of Screen

(Feet) 2-In., //1. 6 Lens 3-In., //2.0 Lens 4-In. //2.8 Lens

4*/2 63.0 40.0 20.6

5 51.0 32.5 16.7

6 35.5 22.5 11.6

7 26.0 16.6 8.5

8 20.0 12.7 6.5

9 15.75 10.0 5.15

10 12.75 8.1 4.2

11 10.5 6.7

12 8.85 5.65

13 6.9 4.4

14 6.5

15 5.65

16 5.0

LENSES

Lenses listed as available on carbon arc, 16-mm projectors range
from 3/4 inch to 4 inches in focal length. The sizes usually supplied
as standard equipment are 2-inch, //1. 6 and 3-inch, //2.O. Struc-
tural limitations on some projectors necessitate the use of approxi-
mately the same effective diameter for lenses of all focal lengths so
that increase in focal length is accompanied by decrease of lens speed.
However, projectors are available with lenses of //1. 6 speed in focal
lengths ranging from 2 inches to 3l/z inches.

July, 1943]

CARBON ARC PROJECTION

The use of a projection lens with focal length greater than the 2-
inch or 3-inch lens usually supplied with 16-mm projectors is seldom
necessary although it may occasionally be advantageous in locations
where seating arrangement, shape of room, permanent projection
booth, or other condition necessitates a long throw from projector
to screen. Increase in length of throw with a given lens increases
the width of the screen image proportionately and may result in a
larger image than is desirable. Furthermore, the screen brightness
is decreased in inverse proportion to the change in area of screen

FIG. 2. Seating plan for 8-ft screen; capacity
220.

image. Increase of focal length of lens, on the other hand, allows
the throw to be increased in proportion to the change in focal length,
without changing the size of the screen image. However, if the lens
of greater focal length is also lower in speed (//value), less light will
be thrown on the screen. Should the resulting screen brightness
be below the recommended level it is usually preferable to seek some
means of locating the projector closer to the screen to permit use of
the standard projection lens.

The normal optical speed of the 16-mm carbon arc projection lamp
being //1. 6, little is gained by using a projection lens of less than 2-

W. C. KALB

[J. S. M. P, E.

inch focal length in order to obtain higher lens speed and more light
on the screen. Some increase in optical speed of the lamp can be
obtained, to make effective higher lens speed, by decreasing the dis-
tance from mirror to aperture and increasing that from mirror to arc.
However, the principal occasion for using a lens of less than 2-inch
focal length is where the projector must be located relatively close to
the screen and a projected light-beam of wide angle is needed to
obtain the desired width of screen image.

FIG. 3. Seating plan for 11.3-ft screen; capacity 412.

Data on screen light given throughout this paper are based upon
untreated lenses. Lenses that have been treated to reduce reflection
losses and improve the transmission factor are not commercially
available for 16-mm projection at the present time. However, car-
bon arc projection of 16-mm film with untreated lenses meet rec-
ommended standards of projection practice for audiences of such
size that situations are seldom encountered in which there is need
for treated lenses to provide a satisfactory intensity of screen illumi-
nation.

July, 1943]

CARBON ARC PROJECTION
SIZE OF AUDIENCE

The SMPE Committee on Non-Theatrical Equipment has rec-
ommended3 certain procedures and conditions to be observed in the
presentation of 16-mm motion picture film to provide a picture that
can be viewed to good advantage by everyone present. Among
the recommendations made are the following :

(i) Distance of farthest spectator from screen should not exceed 6 times the
width of screen image.

,16 FOOT ,

rsCREEffl

FIG. 4. Seating plan for 16-ft screen; capacity 856.

(2) Distance of nearest spectator from screen should not be less than twice the
width of screen image.

(5) Viewing angle of no spectator should be greater than 30 degrees.

(4) Optimum screen brightness, 10 foot-lamberts measured with shutter
running but without film.

(5) Limits of screen brightness, not more than 20 foot-lamberts or less than
5 foot-lamberts, measured as above.

(6) Color-temperature of the light delivered to the screen to be in the range
from 3000° to 4700°K.

(7) The use of matte type of screen "in all cases where a projector of adequate
illuminating power can be obtained."

100 W. C. KALB

The report further points out that a 2-inch, //1. 6 lens fills the screen
at a distance equal to 5L/4 times the screen width.

From Table I it may be observed that, with a matte surface screen
of 75 per cent reflectivity and a 2-inch, //1. 6 lens, high-intensity car-
bon arc projection of 16-mm film provides the maximum recom-
mended level of screen brightness with an image 8 feet in width and
fills a 16-foot screen at the minimum limit of brightness. The cal-
culated image width at optimum brightness of 10 foot-lamberts is
11.3 feet. Color-temperature of the light is within the range rec-
ommended by the committee.

Figs. 2, 3, and 4 represent seating plans conforming to the rec-
ommended limits of viewing angle and distance from screen for the
three conditions of screen width and brightness named in the pre-
ceding paragraph. Seating capacities are based upon the use of 20-
inch seats, 32 inches back to back, with a limit of 14 seats between
aisles as prescribed by the laws of some states. Fig. 2 shows that
advantageous presentation of 16-mm film can be made with high-
intensity carbon arc projection, at maximum recommended screen
brightness, before an audience of at least 220 persons. Presentation
at optimum screen brightness can be made before 412 seated specta-
tors with the seating plan shown in Fig. 3 and, at the acceptable screen
brightness of 5 foot-lamberts, before an audience of 856 seated as
indicated in Fig. 4.

Carbon arc projectors are now available from several of the larger
manufacturers of 16-mm projection equipment. The increased screen
size that can be adequately illuminated by these carbon arc projectors
greatly extends the utility of 16-mm film for educational, commercial,
and other purposes. It makes practicable the showing of a 16-mm
picture before a comfortably seated audience of several hundred under
conditions conforming to the best standards of projection practice.

REFERENCES

1 STRONG, H. H. : "A High-Intensity Arc for 16-Mm Projection," J. Soc. Mot.
Pict. Eng., XXXIII (Nov., 1939), p. 569.

2 LOZIER, W. W., AND JOY D. B. : "A Carbon Arc for the Projection of 16-Mm
Film," /. Soc. Mot. Pict. Eng., XXXIV (June, 1940), p. 575.

8 "Report of the Committee on Non-Theatrical Equipment," /. Soc. Mot.
Pict. Eng., XXXVII (July, 1941), p. 22.

THE PRACTICAL SIDE OF DIRECT 16-MM LABORATORY

WORK*

LLOYD THOMPSON**

Summary. — Laboratory practice for direct 16-mm production differs somewhat
from 35-mm methods. Thiriy-five-mm laboratory practice is confined largely to nega-
tive-positive, and 35-mm color is done mostly by special service laboratories and not
by the studio or release-print laboratories.

Direct 16-mm production calls for the reversal type of processing, the negative-
positive method, and color developing. Some producers own laboratories for doing
the first two, but color is processed by the manufacturer. However, independent labo-
ratories are printing color. This paper describes how some of these processes are
used in direct 16-mm production, especially when the methods differ from conven-
tional 35-mm practices.

There have been a lot of theories expounded as to how 16-mm
laboratory work should be done. A number of them have been based
upon anticipation of what the film manufacturers may be able to
offer in the future. But we, the people engaged in making 16-mm
motion pictures in order to earn a living, can not wait until all these
problems have been worked out. Sometimes we have to forget the
theory as worked out by the best laboratories doing 35-mm work and
use a method that will do the job even though it may not conform to
theory.

This does not mean that we are not grateful for the theory as
worked out by these laboratories and practiced by the producers of
35-mm film, because we are. A great many of their theories work
equally well in 16-mm practice, and so the problem becomes one of
when should we use 35-mm methods on 16-mm films and when should
we disregard the methods and theories and start using some other
method of production or laboratory procedure. The answer is prob-
ably quite simple. Begin by using the procedure that is recom-
mended, and if it does not work try something else. To say that

* Presented at the 1942 Fall Meeting at New York, N. Y. ,
** The Calvin Company. Kansas City, Mo.

101

102 L. THOMPSON [j. s. M. p. E.

such a cut-and-try method of arriving at a standard should be a
standard for all time to come would be foolish. The procedures out-
lined in this paper have been used in actual production work and are
being used today. We constantly try out new ideas and new meth-
ods and when such a method proves itself to be better or more prac-
ticable, the new procedure is adopted.

Laboratory practice for direct 16-mm work may be divided into
several divisions:

(1) Original photography.

(2) Sound-tracks.
(3} Prints.

Each of these may be further subdivided. We shall begin with
original photography as it is known at the present time :

(1) Black and white.

(a) Reversal.

(b) Negative and positive.

(2) Color.

Most of the recognized 16-mm producers today use reversal film
in shooting their original black-and-white pictures. However, there
is a growing tendency to use Kodachrome even for black and white.
In such cases the original is made in color and the black-and-white
prints are made from dupe negatives. There are several things to
recommend the procedure.

The arguments for using reversal film for the original picture have
been listed before, but we may summarize them briefly by saying
that reversal film gives finer-grained originals and excellent tone
quality. Dirt spots do not show up as objectionably as on negative
film, and the original film can be more easily handled and spliced be-
cause 16-mm splices made on reversal film do not show up on the screen
as they do with negative film. The first cost of reversal is less. The
laboratory set-up for 16-mm reversal film is well standardized through-
out the world, and one can be assured of getting fairly consistent
results at any of these laboratories. Sixteen-millimeter reversal
film is readily accessible almost anywhere. The material lends it-
self well to making dupe negatives so that the original can be pre-
served.

Some of the objections that have been raised to the use of reversal
film are that it does not have as much latitude as the negative-positive
process. It is said to be more critical in exposure. The photog-
rapher does not have the corrective latitude in making the prints after

July, 1943] DIRECT 16-MM LABORATORY WORK 103

the original has been processed that he does with negative-positive.
Some of these things are probably true. The film does take special
handling in that the lighting must be somewhat different from that
used for negative-positive film and the exposure should be as nearly
correct as possible. However, this should not work any hardship
on the cameraman who is working with direct 16-mm in a professional
way, because he will probably be called upon to handle both black-

FIG. 1. One-to-one optical sound-printer for 16-mm.

and- white and color. Color is a reversal process and must be
handled in much the same way as black-and-white reversal. For that
reason the cameraman must be capable of using an exposure meter
in such a manner that he is able to get consistent exposures, and he
will also be in the habit of lighting for color-film. It is true that there
is some difference in the lighting for Kodachrome and black-and-
white reversal, but probably not as much difference as there is be-

104 L. THOMPSON [j. s. M. P. E.

tween Kodachrome and negative film. In making a black-and-white
production by the reversal method the cameraman should always try
to have enough film of one emulsion number on hand to do the com-
plete job. He should decide to what maximum density he wishes
the film developed in order to get the results he wants. Usually
this maximum density will be approximately 2.1 to 2.3. He should
then make tests with the type of film he expects to use, at different
exposure levels, and have the film developed to the correct maximum
density. From this series of tests the cameraman can pick out the
exposure most nearly correct and thus set his exposure meter so that
he can duplicate the results throughout the production. If these
simple precautions are taken he should have no trouble in getting con-
sistent results. He should inform the laboratory doing his work
what he is trying to do, and it is necessary in sending such black-and-
white films to the laboratory to enclose a note with them stating
what is wanted. If the cameraman is having his film developed to a
specific maximum density, he should allow enough blank film on one
of the rolls for the laboratory to run an actual developing test so that
they can be certain of getting the correct density. In doing profes-
sional work with 16-mm film the producer must remember that the
reversal laboratories are set up to process amateur film. There are
some laboratories that use automatic exposure compensation to cor-
rect exposure errors. For average amateur films this is perfectly all
right, but the maker of professional pictures usually does not want
this. There are other laboratories that develop to a certain maximum
density and depend upon the cameraman to give the correct expo-
sure. Both methods have their advantages and disadvantages, but
the professional user will usually do better to give the film the correct
exposure and then have it developed to a specified maximum density.
In developing amateur film the reversal laboratory receives each day
many different emulsion numbers from different customers. Some
of this film may be out of date, some of it may be almost out of date,
and other rolls may be fresh film. Some of it may have been stored
under bad conditions and other rolls will have been kept under ideal
conditions. Different batches of emulsion will vary, and as a result
some of the rolls may be developed in such a way that they would not
meet standards of the professional. For that reason it is a good idea
to send a test strip along with each batch of film sent in for processing
and to specify the maximum density to which the film is to be de-
veloped.

July, 1943]

DIRECT 16-MM LABORATORY WORK

105

The criticism has been made of reversal film that it does not have
as much latitude as negative-positive. Practical experience has
shown that if an exposure meter is used consistently the latitude is
sufficient for all practical purposes and by making light-changes in
the prints the films can be evened out very successfully. Extreme
under- or overexposure is, of course, very difficult or impossible to
correct in printing. But this may also be true of 16-mm negative-
positive. Because of its size, 16-mm film must be more nearly cor-

FIG. 2. Wet end of a 16-mm reversal processing machine.

rectly exposed than larger films, whether reversal or negative-posi-
tive.

The criticism has been made also that reversal films are not espe-
cially suited for shooting under adverse conditions. The statement
has been made that many times it is impossible to light a subject
sufficiently and it is necessary to bring it out by overdevelopment of
the negative, and that this can not be done in reversal. This is not
the case. There are times when the cameraman does not have
enough light on the scene and yet he must make the shot. In such a
case he should shoot the scene that does not have sufficient light and

1061 L. THOMPSON [j. s. M. p. E.

keep the film separate from the rest of the film. He should also shoot
some extra footage on this particular scene at the same exposure he
used in making the test. He should give this to the laboratory for
test and ask them to overdevelop it so as to give the best results.
The laboratory can then take the extra footage and run one test or,
perhaps, several tests, in order to find exactly how much the film
should be overdeveloped in order to get the best results from that par-
ticular roll. This is extra work for the laboratory but most labora-
tories are willing to cooperate. Such tests require extra time and
when something special is wanted the lab should be allowed some ex-
tra time in order to perform the necessary tests to get the best results.

While it is possible to get good results with rack-and-tank develop-
ing, automatic machine processing gives more consistent results from
day to day. Most producers of 16-mm film will find it to their advan-
tage to use the laboratory that offers machine processing. Practically
all film manufacturers offer such a service, and any of the standard
films on the market offer laboratory service where machine processing
is available. Occasionally some 16-mm film producer will attempt
to use an off -brand film or try to process a negative film as reversal,
and naturally the results are disappointing. Standard-brand films
should be used, and certain types of emulsions will do a better job
than others. The user will therefore have to learn which emulsions
give best results for his purpose and he should then try to stick with
that particular type of emulsion. He should, of course, try new
emulsions as they are offered from time to time, and there are times
when the cameraman wants some effects that can be made only by
using a special emulsion. He may even want to use positive film and
reverse it.

Most of the direct 16-mm producers have probably started with
the idea that the way to shoot 16-mm commercially would be to use
negative film and make positive prints from it just as they do in
Hollywood. There has been a great deal of effort spent in trying to
develop a laboratory procedure that would be entirely satisfactory
for 16-mm commercial work done in this manner. Some very good
work has been done, but there are still a number of things about the
process that make it impracticable for most commercial purposes.
The time may come when these defects will be corrected.

A great number of developers have been tried with negative film.
There are the common borax-type formulas which are well known in
the 35-mm industry. There have been other special formulas in-

July, 1943]

DIRECT 16-MM LABORATORY WORK

107

volving the use of paraphenylenediamine and various combinations
of chemicals. These formulas have been worked out in an attempt
to get fine-grain quality from original negatives that would match
the fine-grain characteristics of reversal film. The use of fine-grain
positive has done a great deal toward reducing the graininess. Also,
the original negative can be developed to a lower gamma and the
positive print to a higher gamma, which makes for finer grain.

In developing 16-mm negative film it is extremely important that
the film be developed to the correct gamma. It is important also
that the processing be very clean because dirt spots become very ob-
jectionable white spots on the positive print. Negative film is also

FIG. 3. The testometer, used for checking timing,
a time-scale sensnometer.

The left side contains

very susceptible to scratches and any scratch, no matter how slight,
either on the back of the base or on the emulsion side, will show up
on the positive print as an objectionable white line.

Because 16-mm negative film is so susceptible to scratches and dirt
and because the splices made in negative film show up as objection-
able white lines on the screen, it is extremely difficult to handle in
regular production work. The same precautions should be observed
in shooting negative film as in shooting reversal. That is, it should
be properly exposed, different emulsions should not be mixed to-
gether in the same production unless it is absolutely necessary, and
the producer should have the full cooperation of the laboratory in

108 L. THOMPSON [j. S. M. P. E.

getting the most out of his negatives. Machine processing is highly
desirable.

At the present time the only commercial process for shooting 16-mm
color originals is Kodachrome. Kodachrome is developed only in
the laboratories of the manufacturer of the film, and here we might
say the customer has no control over the laboratory practice in de-
veloping the film. We might also assume that the customer needs
to take no special precautions because the laboratory procedure on
Kodachrome will be consistent from day to day, and thus the results
will be the same. This is not exactly true. We in the 16-mm busi-
ness quite frequently see films that have been shot by some amateur

FIG. 4. Using the testometer as a sensitometer.

photographer to be used in a commercial film. He has taken no
special precautions as to using one emulsion number throughout the
picture or through one particular sequence, or as to sending all of the
picture, or all of the pictures in a sequence, for processing at one time.
As a result we quite frequently see pictures in which the color balance
changes considerably. On the other hand, we have shot a number of
Kodachrome pictures and have not been annoyed with this change in
color balance to any degree. However, there are certain precautions
to be observed. If possible, we usually try to shoot an entire picture
on one batch of emulsion or at least we try to shoot one particular
sequence on one particular emulsion number. If possible we also

July. 1943] DIRECT 16-MM LABORATORY WORK 109

like to shoot one entire sequence or an entire picture and send it in for
processing all at one time. The laboratory that develops our Koda-
chrome film is aware of the fact that nearly all the Kodachrome which
we send for processing is of a commercial nature, and these
films are never run until they have had a chance to see the work com-
ing from the machine and had a chance to check it to be sure that the
color balance is correct. If the color balance is slightly off, the films
are held until it is as nearly correct as possible, and then the films are
run through. The color balance is never very far off, because in
nearly all cases the films are within very acceptable limits. If the
picture is to be used for commercial purposes it is desirable that
these limits be held within as close tolerances as possible. Here again
we have found the laboratories perfectly willing to cooperate in every
way provided we tell them what we are trying to do.

Just as in 35-mm practice, there are two types of sound-tracks used
in direct 16-mm. However in the 1 6-mm field variable-area predom-
inates. In direct 16-mm there are three types of variable-area tracks
used at the present time. They are :

(a) Negative tracks.

(b) Direct positive tracks.

Variable-area negative tracks are used for:

(1) Printing with original negatives.

(2) Printing with dupe negatives.

(5) For making positive prints for printing with Kodachrome prints or black-
and-white reversal prints.

Variable-area direct positive tracts are used for :

(1 ) Printing directly to Kodachrome.

(2) Printing directly to black-and-white reversal tracks.
(5) For re-recording.

(4) For printing negative tracks where it may be necessary to have several
negative tracks.

Variable-area reversal tracks are used for :

(I) Single-system sound.
(2} Re-recording purposes.

Variable-area tracks are usually developed in regular positive de-
veloper although there have been special formulas developed for
processing variable-area tracks. Since processing machines are
usually set up with positive developer and since these developers are
in constant use, it is comparatively simple to keep the developer at

110 L. THOMPSON [J. S. M. P. E.

the correct potential at all times. Regular lib sensitometric strips
can be run through with the processing during the day and these
strips checked to be sure that the developer is in proper condition
before running sound-tracks. If a special developer is used for sound^
track developing only, it is necessary either to change developers in
the tank or to have a special tank for sound-tracks only. In either
case the developer is not in continuous use, and since there is prob-
ably no laboratory with enough direct 16-mm sound-tracks to keep it
running constantly, it is necessary that a certain portion of the day be
picked for running sound-tracks. If the developers must be changed
it is necessary to check their temperature; also to run either a test of
the sound-track or a sensitometric strip before actually processing
the film. This takes a great deal of time and it is questionable as to
whether this procedure helps the final result. If yellow-dyed record-
ing stock is used with blue light (4000 to 4500 angstroms: Corning
597) for making the original sound-track, the usual procedure is to de-
velop the negative tracks to a density of 1 .8 to 2.0. Gamma is usually
1.8 to 1.85. Positive prints made from such negatives on fine-grain
stock and developed to the proper gamma and density will give good
reproduction and also improve the noise level of the positive track.
Direct positive tracks are not in general use either in 35-mm or
direct 16-mm productions. By direct positive track is not meant
reversal track, but direct positive track produced optically. The
track is developed as an ordinary sound-track, but instead of getting
a negative track we have a positive track, which can be used either
for play-back or for printing by the black-and-white reversal method
or with Kodachrome. It is necessary to have a special galvanometer
for this type of track. According to theory such track does not lead
to good results. However, we have not found that to be exactly
true. Since yellow-dyed stock has been available for recording sound
in direct 16-mm, it has been possible to make good direct 16-mm posi-
tive tracks without very much difficulty. Such tracks must be prop-
erly exposed and developed if good results are to be obtained. The
density becomes rather critical. We have used such tracks for a num-
ber of purposes : for recording music when the music was to be re-re-
corded on another direct positive or negative track for printing; , for
recording original voice which was to be used for re-recording before
printing; and for direct recording when the recording was to be
printed with Kodachrome or with black-and-white reversal prints.
We have also made direct positive tracks, and then dupe negatives

July, 1943] DIRECT 16-MM LABORATORY WORK 111

from them for making positive prints. We have been told many times
that some of the things we are doing are entirely wrong and we simply
should not do them that way. We have conducted a great many ex-
periments along this line and are convinced that for a number of pur-
poses the direct positive will work very satisfactory in direct 16-mm
recording work. If the film is to be used for direct play-back or for
re-recording, the density is kept at 1.2 to 1.3. If it is developed be-
yond 1 .4 the highs usually have a tendency to block slightly. If the
direct positive is to be used for printing with Kodachrome or for
printing black-and-white reversal prints, the density of the direct
positive sound-track can go up to 1.5, 1.6, or even higher. We have
never found any particular advantage in going beyond 1.5 or 1.6, as a
track of this density seems to be about as quiet in the print as one
that has been developed to a higher density. (Some of the new re-
cording stock should be developed to 1.8, 1.9, or higher.) While it is
possible to make direct positive tracks on regular positive release stock,
the developing becomes very critical, and for that reason we have found
the yellow-dyed stock to be much more satisfactory for making this
type of track, as well as for other direct 16-mm recording. Direct
positive tracks are developed in positive developer the same as the
variable-area negative tracks. In production work we attempt to
control the exposure of the original recording so that all tracks can
be developed a normal time in the developer and when different den-
sities are wanted the exposure is changed to give that density. If
emulsion numbers are closely watched and exposure lamps are care-
fully checked and tested before use, it is comparatively simple to get
whatever density is wanted from day to day.

Producers who do not own their own laboratories and must de-
pend upon outside laboratories for developing their original sound-
tracks can get the same results if they will follow certain definite
procedures. One complete session of recording should be recorded
on one emulsion number if at all possible. Lamp currents should
be carefully adjusted and maintained accurately. A test exposure
should be left on one of the rolls of film and this roll clearly marked
as to how much and where the test will be found. The density
wanted on the final track should be clearly indicated. If it is neces-
sary to change emulsions during a session, this should be clearly
indicated and a test left on the new emulsion that is used. If it is
necessary to change recorder lamps during a recording session, this
also should be noted on the film and a test left for the new lamp as

112 L. THOMPSON [j. a M. P. E.

well as the old one. All recording lamps should be checked photo-
graphically before being used. We have found that recording lamps
that are supposed to be prefocused and correctly adjusted will vary
as much as four or five points in density. For that reason we have
made up a special jig for our recorders, and whenever we receive new
lamps they are checked in this jig with a master lamp which we know
gives us maximum exposure. Before doing this we had a great deal
of difficulty in trying to keep our densities correct over a period of
time. All new lamps are first checked in the jig and then inserted in
the recorder ; then a short photographic test is made of them and the
density given by each of the lamps is marked on the lamp. In this
way if the lamp burns out during recording it is possible to select
another lamp having exactly the same characteristics, and proceed
with the recording. It might seem that this is taking a lot of un-
necessary care, but if the film is to be used for commercial purposes
we feel that everything should be as nearly correct as possible, and
it is much cheaper to make these checks than it is to make retakes.
These precautions ar e necessary for a producer operating his own
laboratory even though he has full knowledge of any irregularities that
may take place. Commercial producers who send their work to com-
mercial laboratories must take the same precautions if they expect
the results to be uniform.

Variable-area reversal tracks are usually used with single-system
sound recording. There are several reasons why the reversal system
can not be used in place of the direct positive tracks about which we
have been talking. Most galvanometers do not have enough light
in them to expose positive film or yellow-dyed recording stock suffi-
ciently for the reversal process. Even though the galvanometer
may have enough light for exposing the stock for reversal processing,
the exposure and the developing become very critical. Unless the
exposure and the developing are absolutely correct on positive film
or recording stock, the sound either loses a great deal of volume be-
cause the clear portions do not clear out completely, or the highs are
cut off by overexposure or incorrect developing. If panchromatic film
or Kodachrome is used for recording sound by this method, these de-
fects are not nearly so noticeable. In this case the exposure is not so
critical although enough exposure should be given to clear out the
clear portions of the track, otherwise the volume level becomes very
low and the background noise becomes objectionable. The danger
of overexposure is not so great when this type of film is used. It is

July, 1943] DIRECT 16-MM LABORATORY WORK 113

perfectly satisfactory to record sound on panchromatic film or on
Kodachrome when the picture is being taken at the- same time.
However, most people will not want to use regular panchromatic
film for recording the sound only, as it will be somewhat expensive
and the results will not be as good as is obtained with, for instance, a
direct optical positive. Such film can be used for re-recording pur-
poses quite satisfactorily but it is not suitable for re-printing by the
reversal system. Sound made by the reversal system has a slight
tendency toward distortion due to the spreading of the light-beams
and the procedure used in reversal processing. Therefore, if an origi-
nal reversal sound-track is printed again by the reversal method, this
distortion tends to build up and become rather objectionable. Single-
system sound shot on Kodachrome is also quite satisfactory when the
proper exposure is given and when the sound is used as a direct play-
back. Such sound-tracts are not suitable for printing to another
Kodachrome duplicate. If such sound-tracks must be re-printed, the
best method at the present time seems to be to re-record the sound to
the black-and-white track and then print from that. Re-recording
the sound-track directly on the print is also satisfactory, but in such
case type A stock must be used instead of duplicating stock, as the
dupe stock is too slow to be used in most recorders.

Variable-density has not been used a great deal in direct 16-mm
work. Probably the widest use of variable-density in 16-mm has been
with single-system cameras. It has been necessary that these
cameras use negative film as they were unable to get enough exposure
of the reversal type of emulsion to get a sound-track. Since prac-
tically all the variable-density sound has been made with single-
system cameras, it does not seem that anyone has done very much re-
search on the developing and printing of variable-density direct 16-
mm sound. Since most people shooting single-system variable-
density sound are interested in getting a good picture, negatives are
nearly always developed to get the most out of the pictures and let
the sound take care of itself.

After the original photography has then been shot and the original
sound has been made there is then the question of getting prints, and
the question of getting good prints has been one of the biggest prob-
lems in the 16-mm field. However, this problem has been pretty
well solved during the past few years and practice is becoming fairly
well standardized. We shall consider first the problem of black-and-
white prints.

114 L. THOMPSON [j. s. M. P. E.

The first print wanted from an original is usually a work print.
If the original is reversal or Kodachrome, a reversal black-and-white
work print is made — all on one light. An inexpensive grade of film
such as positive is used for printing, and this is reversed. This gives
a positive image which is easy for the editor to work with. Some
originals are now shot on stock with edge numbers in which case they
can be printed on the work prints. This is the most satisfactory
method of editing except. that the use of edge-numbered stock for
originals is not yet universal. Rush prints, as they are known in the
35-mm field, are usually not used in 16-mm work. Originals are
usually projected for this purpose, and then those scenes that are to
be used are cut out, spliced, and a work print made.

Suppose the original was made on black-and-white reversal film or
Kodachrome. The first method of making black-and-white release
prints from original reversal film was the reversal process. There
were, of course, dupe negatives, but the early dupe negatives were far
from satisfactory. The prints obtained with the reversal system were
good enough that most persons were not able to tell them from origi-
nals. For that reason the reversal process was used almost exclu-
sively for several years in making black-and-white prints from re-
versal originals, as well as in making sound-prints. The method is
still capable of giving excellent results, and when only a few prints
are wanted from an original it is probably the most satisfactory and
the most economical method of making them. The procedure for
making black-and-white reversal prints is well standardized. They
can be turned out in the shortest possible time and there is no added
expense of making a dupe negative.

The most satisfactory solution to printing direct 16-mm sou ad
seems to be the one-to-one optical sound-printer. It gives good
definition, and there is no shrinkage or creepage problem. The re-
sults are consistent from day to day. The printer can be used for
printing all direct 16-mm tracks. If sound is to be added to black-
and-white reversal prints it is necessary to have a positive track of
some sort or other. This positive track can be a positive from a nega-
tive or it can be a direct optical positive. The density of the track
should be 1.5 or more; in any event the density of the original track
for making reversal prints should be quite high. If a reversal print is
made of an original track of low density, there is a tendency to lose
considerable volume. In order to avoid losing this volume it is neces-
sary to print with enough light to clear out the clear portions com-

July, 1943] DIRECT 16-MM LABORATORY WORK 115

pletely. With this rather strong printing light the dark portions of
the track also have a tendency to become lighter in the print, and if
the original is light at the beginning this will be accentuated in the
print. The track is likely to become noisy either from a lack of den-
sity in the dark portions or because of density in the clear portions.
However, original sound-tracks having a density of 1.5 or better
print very satisfactorily on reversal film. Printing reversal tracks
from original optical positive seems to have the same cancelling ef-
fect upon distortion as printing negatives to positives.

If a number of black-and-white prints are wanted from an original
black-and-white reversal film or from Kodachrome film, the cheapest
and most satisfactory method of obtaining them at the present time
is by making a fine-grain dupe negative on panchromatic duplicating
film. This dupe negative is then used for printing positives. The
most satisfactory material for printing the positives at the present
time seems to be the fine-grain positive films that are available. In
making a 16-mm dupe negative it is necessary to be especially careful
that no blemishes or dirt occur in the processing, since they will show
up in the final print and be quite objectionable. It is almost neces-
sary to use a step printer with pilot-pin movement in making these
dupe negatives if proper contact and screen steadiness are to be
achieved. After a steady dupe negative is made, it can then be
printed on a good continuous printer with satisfactory results.
Continuous printers seem to be quite suitable for making any print
where several printing processes are not required.

At this point it might be well to discuss the construction of 16-mm
printers and print rooms. Since several types of film are used and
since they can be worked under different safe-lights, we have found
it advantageous to work each printer in a separate room. Each
operator can use a safe-light suited to the stock he is using without
interfering with any other operator. In some cases we have found it
advantageous to use white-light loading-dark-room printing print-
ers. Original films are usually edited to lengths of 390 feet on 400-ft
reels. Our printers are all constructed to take these reels and we use
cores only for the raw stock. By keeping originals on reels it makes
them easy to handle, store, and check.

In order to make consistently good dupe negatives it is necessary
to use sensitometric strips for checking density and gamma. If the
final release prints are to be of uniform density throughout, it is neces-
sary to use some sort of machine for checking light-changes. This

116 L. THOMPSON [j. S. M. P. E.

check is probably more important in making dupe negatives from 16-
mm originals than it is in 35-mm work. In our own laboratory we
use a machine called a testometer, which was manufactured especially
for us by the Baker Motion Picture Apparatus Company. It is a
combination time-scale sensitometer and light-testing machine. Un-
like many machines which make exposure tests on alternate light
changes on the printer board, this machine has been built to cover a
complete range from one end of the scale to the other on our particu-
lar printers.

It is important that this machine be used for timing, instead of
inspecting the original film visually and then having the operator
judge the correct light-change, because an original picture made on
16-mm reversal film may have a number of different types of film in it.
It may have several different brands of reversal stock developed in
different laboratories. This is not recommended, but such things
happen. It may contain titles made on positive film. It may con-
tain shots taken from 35-mm film and reduced to 16-mm positive
film.

The reversal process has a tendency to deposit a slight yellow tone
in the gelatin of the film. This strain will vary somewhat in the same
laboratory from day to day. It will naturally vary from day to day
with different laboratories and also with different brands of film.
There may be days when there is practically no stain. Different
brands of reversal film will also have different tones due to the char-
acteristics of the emulsion. Usually the finer-grained films have a
tendency to be slightly on the brown side. All these things affect
the printing light, and the operator will have a very difficult time dis-
tinguishing between various tones and setting his printer light cor-
rectly. These tones are usually not deep enough to be objectionable
when the picture is projected but they are deep enough to affect the
printing light considerably.

The procedure used in our laboratory is to make these testometer
exposures on reversal duplicating film and then have them developed
to normal density. The testometer strips are then projected on
a small screen with the same intensity of illumination as would
be used on a normal-size screen. From these tests we are able
to pick the best exposure from each test strip of each scene, and a
dupe negative made in this manner will usually print on one light-
change. Panchromatic duplicating film is exposed in our labora-
tories at the same printing light as reversal duplicating film. This

July, 1943] DIRECT 16-MM LABORATORY WORK 117

machine can be used also for checking color merely by using the light
of the proper color-temperature with the correct filter.

Once the correct dupe negative has been made from an original
black-and-white reversal or colorfilm positive, prints are then made;
and if the negative has been correctly made the positive prints will
be of excellent quality with good detail, good tone quality, and fine
grain. Dupe negatives, like original negatives, are very susceptible
to dirt and scratches, and the utmost care must be used in handling
them because the slightest scratch or piece of dirt will show up in the
final print as an objectionable white streak or spot. If such a nega-
tive is ruined or worn out, another negative can, of course, be made
from the original, and one can start all over again. When a large
number of black-and-white prints is wanted, a dupe negative has a
definite advantage over prints by other methods. If the original
has been edited with masks for trick effects, these masks are run at
the same time. The effects will then be in the dupe negative and will
appear in the positive prints.

If original negatives are used for making positive prints, it is neces-
sary to time them for light-changes and then print them just as one
would print from dupe negatives. It is difficult to say how many
prints can be made from an original negative before it becomes worn
or scratched, as this depends entirely upon the handling of it and the
type of printer used. The procedure for handling original negatives
and dupe negatives, and the printers used for printing them, are con-
tinually being improved, and as they are improved more prints can
be made from each negative.

At the present time the most successful method of making color-
prints from original Kodachrome is to print on Kodachrome duplicat-
ing film. As yet, the results of making a master print corresponding
to a dupe negative and making prints from it are not entirely satis-
factory. That, of course, would be the ideal way of making prints,
but to date all Kodachrome prints are made directly from the original
when the best quality is desired. When various laboratories began
to print Kodachrome, one of the biggest worries was how many prints
could be made from the original before it was worn out. We do not
yet know the answer, but there have been instances where 250
prints have been made from an original. There is one thing peculiar
about printing Kodachrome. The base side of the film can become
quite badly scratched and abraded, but most of the marks do not
show up in the print. Small scratches or abrasions on the base that

118 L. THOMPSON

would be utterly disastrous to a black-and-white dupe negative do
not seem to print on Kodachrome. It is only when there is dirt on
the film or when the scratches become very deep and black that they
seem to show up on the print. Ordinary 16-mm printers that have
been used for black-and-white printing only must usually be con-
verted before they can be used for printing Kodachrome. Koda-
chrome duplicating film takes a great deal more light than any other
film used in 16-mm printing. Some printers can be converted to give
the extra amount of light, and if the printer is still used for printing
black-and-white, some method must be used for reducing the light for
the other stock. This can be done by changing lamps or by using
neutral density filters. Instruction for balancing the light for Koda-
chrome printing can be obtained from the Eastman Kodak Company,
but such directions will probably serve only as a guide in setting up
any particular printer. We have set up several printers for Koda-
chrome printing and in each case it has been necessary to use a differ-
ent filter set-up, even though the lamp temperatures were the same,
as nearly as we could tell with the color-temperature meter and by
referring to the charts of the lamp manufacturers. Once the printer
has been balanced for color-printing, it is usually a good idea to print
tests on it over a period of a week or two and have them processed
on various days before putting the printer into actual production.
If this is done it may be found that slight additional corrections are
desirable to give the best average results. We have already discussed
sound-printing on black-and-white reversal film. The printing of
sound on Kodachrome film does not seem to be as critical as on black-
and-white. Optical printers seem to be the most satisfactory for the
sound, and the additional contrast gained is an advantage. Sound
printed by contact on Kodachrome can also be quite satisfactory.

A direct optical positive, or a positive from a negative will make a
good Kodachrome print. The best density of this track seems to be
1.4 to 1.6. A few exposure tests should be run on the Kodachrome
and after processing the print should be played on several reproduc-
ing units. Such tests should be conducted at periodic intervals.

SOCIETY ANNOUNCEMENTS

FIFTY-FOURTH SEMI-ANNUAL TECHNICAL CONFERENCE
OF THE SOCIETY

At the meeting of the Board of Governors held at the Hotel Pennsylvania,
New York, on May 3rd, it was decided to hold the Fifty-Fourth Semi-Annual
Technical Conference of the Society at Hollywood. The headquarters will be the
Hollywood-Roosevelt Hotel, and the dates October 18th to 22nd, inclusive.

The Chairman of the Papers Committee for the Meeting will be Dr. C. R. Daily.
The personnel of the Papers and other Committees will be announced in the next
issue of the JOURNAL.

Those intending to submit papers for the Conference should communicate as
early as possible with Dr. Daily, at Paramount Pictures, Inc., 5451 'Marathon St.,
Hollywood, Calif.

MID-WEST SECTION

Due to the declining activity of the Mid- West Section of the Society during the
past several years, the Board of Governors, at their meeting at New York on
May 3rd, took action to discontinue the Section.

There will thus be two Local Sections of the Society: (1) the Atlantic Coast
Section, comprising members of the Society resident in the Eastern and Central
Standard Time Zones, and (2) the Pacific Coast Section, comprising members
resident in the Mountain and Pacific Standard Time Zones. Members of the
former Mid- West Section will be affiliated with either the Atlantic Coast Section
or the Pacific Coast Section according to their places of residence.

MAILING OF NOTICES TO MEMBERS OF THE
ATLANTIC COAST SECTION

As the territory included by the Atlantic Coast Section of the Society extends
from Maine to Florida and includes the Eastern and Central Standard Time
zones (as the result of the discontinuance of the Mid- West Section), many of the
members of the Section find it impossible to attend the monthly meetings and
other functions. The situation has been considerably aggravated by the present
difficulties of transportation.

For these reasons, as well as for reasons of economy, the Board of Governors,
at the meeting held on May 3rd at New York, felt that notices of meetings,
routine letters, and other material should be sent only to members of the Section
residing in the New York metropolitan area, since it is from this area that the
meetings draw practically all their attendance.

However, the Board provided also that members not residing in the New York
metropolitan area but who wish to receive such notices, etc., may have their names
continued upon the mailing list of the Section by writing to the office of the
Society, at the Hotel Pennsylvania, New York, N. Y.

119

120 SOCIETY ANNOUNCEMENTS

THE ASSOCIATION FOR SCIENTIFIC PHOTOGRAPHY

The following announcement concerning the formation of The Association for
Scientific Photography has been received from Mr. Donald McMaster, of Kodak
Ltd., England:

Within recent years there has been a ^ery marked increase in the use of photog-
raphy as a scientific instrument in applied science and industry. It is felt that
the majority of workers in these fields are working quite independently of others
similarly engaged and that a new organization catering for their special photo-
graphic requirements would be of considerable value.

An Association for Scientific Photography has accordingly been formed, mem-
bership of which is open to any person actively engaged or interested in the use of
kinematography or photography as a scientific instrument.

The Committee of the Association consists of the following persons : Prof. J. Yule
Bogue (Chairman), S. Boyle, Miss K. C. Clark, G. A. Jones, E. H. Le Mon, Dr. H.
Mandiwall, C. D. Reyersbach, G.H. Sewell, R. Mc.V. Weston (Organizing Secretary).

The aim of the Association is not only to promote interest in the use of photog-
raphy in all branches of science, technology, and medicine, but also to assist its
members in applying photographic methods to the solution of particular problems.

The Association proposes to establish what might be termed an Information
Bureau containing, as far as possible, full particulars of the activities of all mem-
bers and, in suitable cases, the existence and whereabouts of specialized photo-
graphic apparatus and equipment. These data will be used by the Association
for the benefit of members as a "pool" from which information may be drawn on
the very varied applications of photography to research, industry, and teaching.

Use will also be made of this information to enable personal contacts to be
made between members working in similar fields and also to facilitate visits by
members who may be using similar photographic procedures, to the laboratories
of other members.

The field covered by the Association will be a very wide one, and will include
photographic processes of all kinds, such as radiography, color photography, pho-
tomicrography, and in particular, sub-standard cinematography in all its branches.

The Association will endeavor to obtain for members information on practically
any photographic problem which may arise in the prosecution of scientific work.

Meetings will be arranged from time to time at which short papers will be
delivered, to be followed by discussion and practical demonstrations of apparatus
and methods by members. The frequency with which such meetings can be held
will depend to some extent, upon wartime conditions. It is the intention of the
Association to publish a Journal as soon as circumstances permit.

The Association is anxious to foster the production of sub-standard films for
research and teaching purposes, and will endeavor, as far as possible, to raise
the standard of the method of presentation of such films, which at the present
time is low. Members will be able to obtain information on methods of produc-
tion and methods of presentation of films of scientific interest.

Further activities will be undertaken by the Association according to the de-
mand made for such services.

Announcements of meetings will be made from time to time, and any person
requiring further information or particulars of membership is invited to com-
municate with the Organizing Secretary, R. Me. V. Weston, whose present ad-
dress is: Houndwood. Farley. Salisbury, Wilts, England.

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

VOLUME XLI • • • AUGUST, 1943

CONTENTS

PAGE

Recent Developments in Sound-Tracks

E. M. HONAN AND C. R. KEITH " 127

Operations of Army Air Force Combat Camera Units in
the Theaters of War R. JESTER 136

Developments in the Use of Motion Pictures by the
Navy W. EXTON, JR. 141

Problems in the Production of U. S. Navy Training
Films O. GOLDNER 146

The 16-Mm Commercial Film Laboratory

WM. H. OFFENHAUSER, JR. 157

The Projection of Motion Pictures H. A. STARKE 183

Application and Distribution of 16-Mm Educational
Motion Pictures F. W. BRIGHT 190

The Fifty-Fourth Semi-Annual Technical Conference of
the Society, Hollywood, Calif., October 18-22, 1943 195

Society Announcements 199

(The Society is not responsible Jor statements of authors.)

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

SYLVAN HARRIS, EDITOR
ARTHUR C. DOWNES, Chairman

Board of Editors

JOHN I. CRABTREE ALFRED N. GOLDSMITH EDWARD W. KELLOGG
CLYDE R. KEITH ALAN M. GUNDELFINGER CHARLES W. HANDLEY

ARTHUR C. HARDY
Officers of the Society
** President: HERBERT GRIFFIN,

90 Gold Street, New York, N. Y.
*' 'Past-President: EMERY HUSE,

6706 Santa Monica Blvd., Hollywood, Calif.
**Executive Vice-President: LOREN L. RYDER,
5451 Marathon Street, Hollywood, Calif.
^Engineering Vice-President: DONALD E. HYNDMAN,

350 Madison Avenue, New York, N. Y.
** Editorial Vice-President: ARTHUR C. DOWNES,

Box 6087, Cleveland, Ohio.
* Financial Vice-President: ARTHUR S. DICKINSON,

28 W. 44th Street, New York, N. Y.
** Convention Vice-President: WILLIAM C. KUNZMANN,

Box 6087, Cleveland, Ohio.
^Secretary: E. ALLAN WILLIFORD,

30 E. 42nd Street, New York, N. Y.
^Treasurer: M. R. BOYER,

350 Fifth Ave., New York, N. Y.
Governors

*H. D. BRADBURY, 411 Fifth Avenue, New York, N. Y.
*FRANK E. CARLSON, Nela Park, Cleveland, Ohio.
*ALFRED N. GOLDSMITH, 580 Fifth Avenue, New York, N. Y.
*A. M. GUNDELFINGER, 2800 S. Olive St., Burbank, Calif.
*CHARLES W. HANDLEY, 1960 W. 84th Street, Los Angeles, Calif.
*EDWARD M. HONAN, 6601 Romaine Street, Hollywood, Calif.
*JOHN A. MAURER, 117 E. 24th Street, New York, N. Y.
**WILLIAM A. MUELLER, Burbank, Calif.

*HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood, Calif.
**H. W. REMERSHIED, 716 N. La Brea St., Hollywood, Calif.
**JOSEPH H. SPRAY, 1277 E. 14th Street, Brooklyn, N. Y.
**REEVE O. STROCK, 195 Broadway, New York, N. Y.

*Term expires December 31, 1943.
**Term expires December 31, 1944.

Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.

Publication Office, 20th & Northampton Sts., Easton, Pa.

General and Editorial Office, Hotel Pennsylvania, New York, N. Y.

Entered as second-class matter January 15, 1930, at the Post Office at Easton,

Pa., under the Act of March 3, 1879. Copyrighted, 1943, by the Society of Motiou

Picture Engineers, Inc.

RECENT DEVELOPMENTS IN SOUND-TRACKS*
E. M. HONAN** AND C. R. KEITHf

Summary. — Photographs and dimensions are given for a number of types of
sound-tracks, some of which are in general use and some being experimental types.

The considerable number of types of sound-tracks that have come
into use in the past few years make it desirable to agree upon stand-
ard dimensions and nomenclature in order to avoid confusion. Steps
in this direction have been taken with the publication of "Dimen-
sional Standards for Motion Picture Apparatus," in the JOURNAL of
this Society (XXIII, Nov., 1934, p. 247) and in a Bulletin of the Re-
search Council of the Academy of Motion Picture Arts & Sciences,
"Standard Nomenclature for Release Print Sound-Tracks" (Novem-
ber 24, 1937). However, in the several years since the publication of
these standards, the number of types of sound-tracks in common use
has considerably increased. It is, therefore, the purpose of this paper
to publish illustrations and brief descriptions of the most commonly
used tracks and also some experimental tracks in order that suitable
dimensions and nomenclature may be agreed upon and adopted as
standards.

The accompanying illustrations show twenty types of sound-tracks
and combinations of tracks used on 35-mm film. The illustrations
are grouped according to the type of track and without regard to the
relative importance or extent of use. The description of each track
is intended primarily for identification since a discussion of the rela-
tive merits of the various types would require a very extensive paper.
However, references are given to previous publications where more
complete descriptions of the tracks may be found. All the illustra-
tions show positive prints.

The first group of tracks shown are of 100-mil variable-density

* Presented at the 1942 Fall Meeting at New York, N. Y.
** Electrical Research Products Division, Western Electric Company, Inc.,
Hollywood, Calif.

t Electrical Research Products Division, Western Electric Company, Inc.,
New York, N. Y.

127

128

E. M. HONAN AND C. R. KEITH

[J. S. M. P. E.

type. It will be noted that "100 mil" and "200 mil" refer to the
width of film allotted to one or more tracks. Descriptions of the
"squeeze- track" and "push-pull" features will be found in the refer-
ences associated with tracks of these types. The use of noise-reduction
in variable-density recording may be observed on the film as an in-
crease in average density in those portions having low modulation,
although this is not apparent in the small sections shown in the ac-
companying illustrations.

(a) Single Variable-Density (100- Mil). — This is a standard release track and is
the same as Fig. 1 of the Academy Bulletin.1- 2- 3

(b) Single Variable-Density Squeeze. — This is the same as track a except that
the width is varied to increase the volume range. It is the same as Fig. 2 of the
Academy Bulletin. The width may be varied by bringing the two outer margins
closer together, as shown ; by keeping the outer margins fixed and inserting a black
centerline of varying width, or by a combination of the two previous methods.
Since the maximum track width is 76 mils, the amount of squeeze illustrated rep-
resents a reduction of sound level of only about 3 or 4 db.4- 5

A-.076-Y

(c) Push-Pull Variable-Density. — The two tracks are similar to a but are each
47.5 mils wide and 180° out of phase. This is the same as Fig. 7 of the Academy
Bulletin.6

Aug., 1943] RECENT DEVELOPMENTS IN SOUND-TRACKS

.,04 7 5". JO 4 7 5;

129

(J) Push-Pull Variable-Density Squeeze. — This is the application of squeeze-
track methods to the push-pull track, c. It is the same as Fig. 8 of the Academy
Bulletin.5

The next group are of the 100-mil variable-area type. Each is
"Class A" unless otherwise noted. (See track h.)

(e) Unilateral Variable- Area. — Noise-reduction is indicated by the change in
width of the right-hand black margin. It is the same as Fig. 4 of the Academy
Bulletin.7- 8- 9- 10- n

(/) Bilateral Variable- Area. — Noise-reduction is indicated by the change in
average width of the clear center portion of the track. It is the same as Fig. 5 of
the Academy Bulletin.11- «

130

E. M. HONAN AND C. R. KEITH

[J. S. M. P. E.

GO Duplex-Variable-Area. — Noise-reduction in this case is indicated by a
variation in the distance between the two black borders. It is the same as Fig. 6
of the Academy Bulletin.13

(h) Push-Pull Variable-Area — Class A. — The term "Class A" means that each
half of the push-pull record is complete and may be separately reproduced with
comparatively little distortion. In the example shown each half is a unilateral
track and the out-of -phase relation is shown by the fact that a dark projection on
one side is always exactly opposite a white indentation on the other side. The
same effect is obtained if each half of the push-pull track is recorded as a bilateral
variable-area track. Noise-reduction is indicated by a variation in the distance
between the two black borders. This is the same as Fig. 9 of the Academy Bulle-
tin."

(i) Push-Pull Variable-Area — Class B. — In this case one-half of the push-pull
record represents only the positive half of the original wave and the other the nega-
tive half, so that the two halves must be reproduced with equal amplitudes and
in opposite phase in order to avoid distortion. Since the print is opaque except
where modulated, the usual bias type of noise-reduction is not required. The
individual tracks may be bilateral, as shown in the illustration, or they may be
unilateral.11- 12' 13

Aug., 1943] RECENT DEVELOPMENTS IN SOUND-TRACKS

131

(j) Push-Pull Variable-Area — Class A-B. — In this type of track low modula-
tion is recorded as Class A (each track records both halves of the original wave)
but as the modulation is increased it is changed to Class B by recording the addi-
tional amplitude with the positive waves on one track and the negative waves on
the other. Noise-reduction is not used in this type of sound-track.14

The next group of tracks occupy a width of 200 mils and are con-
sequently not used on present standard combined sound and picture
prints.

(k) 200-Mil Variable-Density. -
variable-density tracks.6

-This is a push-pull combination of two 100-mil

(1) 200-Mil Variable-Area Center Shutter. — This consists of two 100-mil bilateral
Class A variable-area tracks in push-pull relation. Noise-reduction is accom-
plished by blocking out a portion in the center of each track.18 ! . \ '

Each of the remaining combinations of tracks includes a "control-
track" together with one or more sound-tracks. The control- track
is generally used to vary the sound level in the reproducing system in
such a manner as to increase the volume range or the signal-to-noise

132

E. M. HONAN AND C. R. KEITH

[J. S. M. P. E.

ratio or both. It may be either amplitude- or frequency-modulated,
and may be distinguished in the illustrations by its resemblance to a
constant-frequency record. The word "comprex" refers to a system
in which automatic volume compression and expanison are used.

(ni) 100-Mil Variable-Density Comprex. — Both sound and control-tracks are
50 mils wide and occupy the space normally used for a standard single 100-mil
track. Track dimensions are the same as for track c.u

A\005"

(n) 100-Mil Unilateral Variable-Area Comprex. — This is a combination of two
half-width variable-area tracks which may be scanned by the same equipment
as is used for track w.16

(0} 200- Mil Bilateral Variable-Area Comprex. — This track is intended for the
same type of sound system as tracks m and n but utilizes a width of 200 mils.16

(p) Three- Channel Stereophonic Comprex. — This arrangement consists of three
100-mil bilateral variable-area sound-tracks, one for each of three stereophonic
channels, and a fourth 100-mil bilateral variable-area track on which are recorded
the compression and expansion controls for all three channels.16- 17- 18

Aug., 1943] RECENT DEVELOPMENTS IN SOUND-TRACKS

133

THREE .080"SIGNAL TRACK

/— 325"--/oNE.080"CONTROL TRACK'

(q) 100^ Mil Variable-Density — 5- Mil Control. — This consists of a single vari-
able-density track having the dimensions of a standard 100-mil release-print
track, with the addition of a 5-mil-wide control-track located in the black region
between sound-track and picture. In practice the control-track is variable-
density, frequency-modulated. The control-track does not interfere with the
playing of a film of this type on a reproducer not equipped for control-track re-
production.19

ONE SIGNAL TRACK

:243"TO <t OF SIGNAL TRACK

7 (

ONE .005 CONTROL TRACK

(r) 100-mil Variable-Area — Sprocket- Hole Control-Track. — This consists of a
standard 100-mil variable-area track plus a variable-area control-track approxi-
mately 100 mils wide located in the sprocket-hole area. The width of the control-
track determines the volume change and may also be used for switching loud
speakers.20

MAXIMUM

AIOOV

134

E. M. HONAN AND C. R. KEITH

tf. S. M. P. E.

(5) Three- Channel Stereophonic Control-Track. — In this case three 22-mil stereo-
phonic sound-tracks occupy the space normally required for a single 100-mil
track. A 5-mil control-track in the same position as in track q records control
signals for each of the three sound-tracks. The sound-tracks and control-track
are all variable-density, the control-track being frequency-modulated.19

THREE.022"SIGNAL TRACKS

.005

ONE.005 CONTROL TRACK

(0 Three-channel — " Fantasound." — This arrangement employs four 200-mil
variable-area push-pull tracks, three being used for sound while the fourth carries
signals for controlling the sound volume in various loud speakers.21

THREE .I65"SIGNAL TRACKS

REFERENCES

(All references are to J. Soc. Mot. Pict. Eng., except the first}

1 Tech. Bull., Research Council, Acad. Mot. Pict. Arts & Sci., "Standard No-
menclature for Release-Print Sound-Tracks" (Nov. 24, 1937).

2 DEFOREST, L.: (May, 1923), p. 61.

» MACKENZIE, D.: XII (Sept., 1928), p. 730.
* MILLER, W. C.: XV (July. 1930), p. 53.

Aug., 1943] RECENT DEVELOPMENTS IN SOUND-TRACKS 135

CRANE, G. R.: XXXI (Nov., 1938), p. 531.

FRAYNE, J. G., AND SILENT, H. C. : XXXI (July, 1938), p. 46.

WENTE, E. C.: XII (Sept., 1928), p. 657.

MARVIN, H. B.: XII (Apr., 1928), p. 86.

MAURER, J. A.: XIV (June, 1930), p. 636.

10 KREUZER, B. : XIV (June, 1931), p. 671.

11 DIMMICK, G. L., AND BELAR, H. : XXIII (July, 1934), p. 48.

12 SACHTLEBEN, L. T. : XXV (Aug., 1935), p. 175.

13 DIMMICK, G. L.: XXIX (Sept., 1937), p. 258.

14 CARTWRIGHT, C. H., AND THOMPSON, W. S. : XXXIII (Sept., 1939), p. 289.
16 LORANCE, G. T., AND BENFER, R. W. : XXXVI (Apr., 1941), p. 331.

16 SNOW, W. B., AND SOFFEL, A. R. : XXXVII (Oct., 1941), p. 380.
17. FLETCHER, H. : XXXVII (Oct., 1941), p. 331.

18 WENTE, E. C., BIDDULPH, R., ELMER, L. A., AND ANDERSON, A. B.: XXXVII
(Oct., 1941), p. 353.

19 FRAYNE, J. G., AND HERRNFELD, F. P.: XXXVIII (Feb., 1942), p. 111.

20 LEVINSON, N., AND GOLDSMITH, L. T.: XXXVII (Aug., 1941), p. 147.

21 GARITY, W. E., AND HAWKINS, J. N. A. : XXXVII (Aug., 1941), p. 127.

OPERATIONS OF ARMY AIR FORCE COMBAT CAMERA
UNITS IN THE THEATERS OF WAR*

RALPH JESTER**

Summary. — The Purpose of Army Air Forces Combat Camera Units is to
supply tactical and operational information in the form of motion picture reports
from the combat zones. This is a specialized activity and requires specialized train-
ing and organization.

The paper describes the course of training for the units and some of the problems
encountered in the field.

In November of 1942, less than six months ago, the Army Air
Forces sent out to the theaters of war the first of its Combat Camera
Units. These units had been activated in what was then called the
Directorate of Photography, Maps and Charts, under Colonel Minton
W. Kaye, to fulfill the need for specialized coverage of the activities
and operations of the Army Air Forces overseas.

The purpose of these units is to supply tactical and operational
information in the form of motion picture reports from the combat
zones. They are instructed to photograph the conditions under
which the Air Forces are operating throughout the world, to cover
combat operations both on the ground and in the air, to secure
photographic and recorded statistical information from pilots and
crew members returning from combat and reconnaissance missions,
record photographically the handling of casualties, battle damage,
new and unusual methods of solving maintenance or mechanical
problems in the field, to report photographically on the development
of bombing patterns and on the altitude and intensity of anti-aircraft
fire over specific enemy positions.

* Presented at the 1943 Spring Meeting at New York, N. Y.
** Major, Headquarters Chief, Editorial Section, Motion Picture Branch,
Army Air Forces, Washington, D. C.

136

AlR FORCE'COMBAT CAMERA UNITS 137

The assignment is pretty broad and consequently the ideal combat
cameraman must function with the dependable efficiency of a trained
motion picture technician, coupled with the unscrupulous inquisi-
tiveness and obnoxious tenacity of the newsreel man. That this
latter quality is certain to be found in one spot at least is evidenced
by the fact that a general recently returned has reported that,
"That damned cameraman is getting in everybody's hair — but I'm
for him!"

This presents one of the key problems of the photographic coverage
of modern war — how these highly specialized technicians can operate
among highly specialized technicians of another sort and what
supplementary military training enables them to do so.

From the beginning of the war, the Germans had already realized
the value of the motion picture camera in a conflict of global propor-
tions. They saw that pictures could bring the field of battle within
view of all, from the general staff to the lowest trainees, as well as
within view of the people at home. And, moreover, the pageant of
victory could be brought to the people who were to be intimidated
by documentary evidence of German prowess. To whatever uses
the German Army may be putting motion pictures now, the or-
ganization for it was developed and put into operation as far ahead
of us as was the rest of their war machine.

The American military mind, with some notable exceptions, was
not as quick to grasp the potential of this medium for reporting
infinitely varied operations on an intercontinental scale. Moreover,
covering the operations of such a thing as an Air Force presented
special problems which, incidentally, are only now beginning to be
mastered.

Such mastery is necessarily based upon the development and care-
ful integration of personnel and equipment, together with trans-
portation, processing, and dissemination.

From the standpoint of personnel, the Air Forces leaned toward
the policy that the making of motion pictures is a highly specialized
activity and is best conducted by individuals who are experienced in
its processes. Consequently, men were sought within the industry,
with emphasis upon actual production experience in the newsreel,
entertainment, or industrial field. The chief of the Motion Picture
Branch, Technical Service Division, AAF, was brought from the
ranks of well known directors; he is Lt. Colonel William J. Keighley.

The course of training for Combat Camera Crews before going

138 R. JESTER ' [J. s. M. P. E.

overseas is tough and thorough. Due to the fact that these men
operate under combat conditions and form part of the regular bomber
crews over enemy positions, it was necessary to decide upon the
advisability of making a machine-gunner out of a cameraman or a
cameraman out of a machine-gunner. It was concluded that a
cameraman is the end product of a great deal of experience, and can
not be turned out in a few weeks.

Consequently the entire complement of each unit undergoes a com-
plete course of military training which includes, among many other
things, flexible gunnery. As you may know, the Air Forces training
program lays particular stress upon the fact that a bomber crew is a
team. To inject into this closely knit group a man who is along for
the ride — "to snap pictures," as the other members might think of
it — would be unwise. It is letting you in on no secret problem of
morale to point out that in some areas this was at one time a factor.
However, if the pilot and his crew feel that the cameraman is capable
of holding up his end, and that he has been trained to know what to
do under fire and can drop his camera for a gtm, he becomes one of
the crew — each respecting the other for his specialized contribution.
Once in the air they all share the same risks.

In this connection, reports have come from the front that three
cameramen have been officially credited with enemy planes. Most
recently, Tech. Sergeant James Bray replaced a wounded gunner
and shot down an ME-109. Lt. Mogen, cameraman, was less for-
tunate— he failed to return from Attu.

Each unit includes several cameramen, a sound crew, still photog-
raphers, drivers, an adjutant, et al., in sufficient numbers to allow
detachments to cover different areas and missions simultaneously.
The impression should not be had that all the enlisted men are from
Hollywood or the newsreel field. This is more nearly true of the
officer personnel, whereas the majority of the enlisted men are from
the field of commercial photography or have been graduated from
the Army Air Forces Photographic School at Lowry Field, Colorado.

Nor is every man in the unit on flying status. Only those whose
duties require them to engage in regular flights for photographic
purposes and have passed the proper physical examination are
classified as air crew members, along with the radio men, gunners,
and engineering crew. Such men wear the crew member wing in-
signia if they have had fifty hours of flying duty as a member of an
aircrew, or have participated as a member of an air crew in an opera-

Aug., 1943] AIR FORCE COMBAT CAMERA UNITS 139

tional combat mission during which exposure to enemy fire was prob-
able and expected, or have been physically incapacitated for further
duty as a member of an air crew while a member of such a crew be-
cause he was wounded as a result of enemy action or injured while
discharging the duties of an air crew member.

Motion picture photography from an airplane presents many and
special difficulties that have long challenged cameramen, engineers,
and designers of equipment. Photographing another airplane or
group of planes or a ground objective from another swift-moving
plane is a difficult job with complex problems involving such factors
as vibration, the slip-stream, obstructions to vision, and temperature.
This is further complicated by the fact that the plane is primarily a
military weapon and the film, except for reconnaissance, can not
strictly be considered such. The cameraman does not shoot to kill;
he shoots to preserve. As a result, his position in the plane receives a
priority after that of the gunner, who must have the greatest range
of vision for the field he is to cover. Various ingenious approaches
have been made to this problem, even to cutting a window in the
leading edge of the vertical stabilizer supporting the rudder. Mounts
have been developed to photograph through the floor and all other
available openings that will not conflict with the functions of the
aircraft; in some instances the cameras are motor-driven and re-
motely controlled by a member of the crew. Shooting through the
plexiglass of the nose is good for certain types of planes and subject
matter, with or without a fixed mount. Hand-held cameras are,
of course, most flexible; but produce pretty jumpy results in atmos-
pheric turbulence or where bumpiness is produced by anti-aircraft
fire.

The units have been provided with the best equipment available;
but in the early stages, at least, this did not always mean a great
deal, because little or nothing was available. Of necessity the equip-
ment is heterogeneous.

I am not at liberty to tell you the exact numbers of either men or
cameras; but there is, roughly, a camera for each man in the unit.
Single-system sound cameras are provided each unit — Audio Akeleys,
Wahls, or Mitchells. Each has several silent motion picture cameras,
either Bell & Howell or Akeley, and several motor-driven Eyemos
with 400-ft magazines. The most numerous types are the hand-
held cameras — Eyemo, Cineflex, DeVry, Filmo, and Victor. For
still cameras there are two speed Graphics.

140 R. JESTER

As mentioned above, one of the photographic objectives of bomb-
ing missions is to provide a film report on the development of bomb-
ing patterns, and to record the altitude and density of flak. In some
areas this is done at extremely high altitudes, with resultant compli-
cations due to low temperatures. Men have risked their lives in the
performance of a job at which they were licked before they started.
One of our men was downed in Crete, later crash-landed in the
Mediterranean and lost his camera, finally got over Naples, at last
had a shot at his objective, and had his camera freeze.

As a result of such discouragements, the building of a special
camera was undertaken, a camera that would not be affected by the
extremes of temperature encountered in the shooting of motion
pictures from planes. Tests on one camera being built for the Air
Force to meet these extremes have proved that this is possible, and
it has functioned perfectly at 65 degrees below zero.

On this planet, at least, it is impossible to expose film under more
varied light and atmospheric conditions than are being encountered
by our combat camera units. From Persia to Guadalcanal, from the
Aleutians to Burma, men are filming Air Force operations under an
infinite variety of handicaps. One crew reports twelve consecutive
missions over Kiska, with increasing Japanese anti-aircraft fire, and
never a hole through the mist to get a shot. Others are nursing raw-
stock through the tropical moisture of New Guinea and watching for
Jap snipers.

If it is your custom, out of courtesy, to accord these papers some
measure of applause, may I be allowed to endorse mine over to the
men of the combat camera crews throughout the world who are faced
with as tough a photographic assignment as has ever had to be put
on film.

DEVELOPMENTS IN THE USE OF MOTION PICTURES
BY THE NAVY*

WILLIAM EXXON, JR.**

Summary. — Naval training films are based upon a complete and continuous
integration of requirements, planning, production, and utilization. This is in
order to provide maximum effectiveness for audio-visual aids. The conditions of
final utilization tend to govern the treatment, the reducing or eliminating the need
for any superfluous content.

Since my last address to this Society, the Navy's use of motion
picture films has been developing extensively and by geometric pro-
gression. Those of you who are in the business of manufacturing
and distributing 16-mm motion picture projector equipment may
have some inkling of the incredibly large number of projectors we
are attempting to acquire.

Those of you who are connected with certain motion picture pro-
ducing organizations will have some conception of the vast range in
the number of productions which we are initiating. Those of you
who are connected with the provision of film stock and with develop-
ing and printing laboratories will have an idea of the enormous
amount of footage we consume. I am not permitted to give you
exact figures in any of these categories, but I believe it is fair to state
that the actual figures would probably seem surprisingly high.

The daily mails bring in numerous requests for films. Every day
we receive dozens of requests for specific titles. Some of the in-
dividual requests list hundreds of titles. The Navy's motion picture
film catalogue, which is not available to the public, is half an inch
thick and contains several thousand items of film and film-strip.
The Navy makes use of films from many sources. Some we derive
from our Allies, some from commercial sources, and others from the
Army and Coast Guard. The Marine Corps produces films, some of
which are valuable for other Naval purposes. Our major source,
however, is production for and by the Navy itself.

* Presented at the 1943 Spring Meeting at New York, N. Y.
** Lt. Commander, U.S.N.R., Bureau of Navigation, Navy Dept., Washington,
D. C.

141

142 W. EXTON, JR. tf. s. M. P. E

As a general rule film production in the Navy originates with a
request from a Naval activity; this activity may be one of the
Bureaus of the Navy Department, it may be the Commandant of a
district, or it may be the Commanding Officer of a training activity.
Such a request for production is normally addressed to the Bureau
of Aeronautics via the Bureau of Naval Personnel. It therefore
reaches the Bureau of Naval Personnel first; and is there subjected
to rather careful scrutiny. A survey is conducted to determine all
comparable parallel or related material, in order that duplication
may be avoided and in order that a knowledge may be had of every-
thing of the kind requested that may already be in existence. It is
then scrutinized from the point of view of utilization ; that is to say,
the request is considered with expert knowledge of the places where
the subject is taught, the conditions under which it is taught, the
numbers of men, and the sizes of the groups to which it is to be
taught. Also considered would be the relationship to other things
that have been or are to be taught to the same men, and any other
matters that affect the eventual utilization of the finished film.
Naval and training policy and doctrine are considered, and a priority
is assigned to the film indicating its relative importance. Any other
suggestions that may seem germane are added, and all this is in-
corporated in an endorsement accompanying the request to the Bur-
eau of Aeronautics.

The Bureau of Naval Personnel may also conduct an extensive
inquiry into the needs for the film, the concept behind it, the ex-
tensive character of the film required; whether the training need
could be served as well by film-strips or even by non-photographic
training aids, such as wall charts or models. Provision is made for
the designation of a technical advisor who will provide official guid-
ance in the Naval aspects of the film. This endorsement accom-
panying the request reaches the Bureau of Aeronautics, where the
Training Film Unit then takes the matter up. This unit of the
Bureau of Aeronautics is charged with arrangements for actual pro-
duction, which involves the selection of a commercial producer or
arrangements with the Photo Science Laboratory. The project
supervisor and an educational consultant are assigned, and these
confer with the technical advisor. The production is then under way.

In many cases, the film in its preliminary stages is referred back
to the Bureau that requested it; in some cases in the form of a script,
and in other cases in the form of an uncut print in the preliminary

Aug., 1943] USE OF MOTION PICTURES BY THE NAVY 143

stages before the sound-track is added. Usually, the technical ad-
visor is present at such a preliminary showing, and final suggestions
may be made before the production is entirely complete. Experience
has shown this sort of final review to be very desirable in many cases.
This is especially so in training films that apply to subjects of wide,
general application; and which are not highly technical, and there-
fore of limited audiences.

Two of the newest developments in the Navy's use of training films
are involved in the post-production stage. They have to do with
the Navy's present practices in connection with distribution and
utilization. The present distribution procedure is to set up allow-
ance lists of training film for each naval activity; that is to say, a list
of the individual titles that each activity should have for permanent
possession, as being particularly appropriate to it. In addition, a
number of training-film libraries are being established in strategic
places. Each of these libraries is thoroughly equipped with films
and also with extra projectors and equipment, and facilities for
projector repair and film renovation. Through these film libraries,
films are available for loan to naval activities everywhere upon
request.

Some fifty highly qualified educators, with special experience in
the field of using audio-visual training materials, have been com-
missioned and are being stationed in training activities where their
advice and guidance in the use of training films and other training
aids are now resulting in the derivation of maximum benefit from the
availability of this material.

In attempting to be brief, I have, of course, eliminated many
details that are important and interesting. It is a fact, nevertheless,
that the Navy's use of motion picture films today is absolutely com-
plete and continuous from the original request through planning and
production to the distribution and the utilization of the film. All
these and every step in each one of these stages are a part of a con-
tinuously planned and integrated program guaranteeing maximum
effectiveness and usefulness of each film. It is not pretended that
every step in the development and use of each film is a perfect one;
nevertheless it is believed that this comprehensive program enables
the Navy to derive benefits from the use of films in training that are
not otherwise available. It is believed that the Navy's experience
in the development of this procedure will be of great value to the
future of educational films.

144 W. EXXON, JR. [J. s. M. P. E.

One tendency inherent in this situation is to get still further away
from the so-called "Hollywood" or "entertainment" technique in
educational or training films. A film is not required to sell itself by
attempting to be witty or amusing. The film is tied into a training
program of which it is a logical and important part. The value
derived from the film, therefore, can be any fraction of the value
that has been put into the film, depending upon the skill with which
the educational program is conducted. Comparatively few films
now being produced by the Navy department rely upon interest-
arousing or interest-exciting superfluousness. On the other hand,
the films are not shown indiscriminately, and therefore the audiences
seeing them know that there is a purpose in seeing them. They are
properly prepared for seeing these films, and the whole situation
surrounding the showing of the film is such as to arouse in them a
recognition of the necessity for deriving from the film all that is
possible.

An example of this is the Night Lookout Training Program. The
Navy has erected a number of Night Lookout Training Centers
provided with stages simulating night conditions and equipped with
ship models of varous types; and with lighting systems permitting
the simulation of dawn, dusk, distant gun fire, and so forth. A com-
petent lecturer utilizes this equipment to demonstrate the principles
of being a good lookout at night and of using the eyes properly at
night. In this connection night or dark adaptation and the physiol-
ogy of the eye become matters of great interest. A film that has
been produced for the Navy, and which illustrates the physiology of
night vision is shown in order to assist in understanding this subject.
The film is technical and contains no entertainment matter what-
ever; and yet under the conditions in which it is shown, it is re-
garded as extremely successful in producing the desired effect by de-
livering the desired information.

Many of the simpler aspects of utilization require attention that
is not often given them. Such simple and obvious matters as proper
projection and proper seating in relation to the screen, so that mini-
mum satisfactory vision is obtained, are matters that may require
guidance. The fact that the average man can not continue to derive
benefit from seeing instructional film for a prolonged period is a fact
that needs to be driven home. Our utilization experts insist that
not more than ten to fifteen minutes of instructional film be shown at
any one time, and this should generally be preceded by introductory

Aug., 1943] USE OF MOTION PICTURES BY THE NAVY 145

remarks and be followed by remarks from the instructor that will
tend to drive home what should have been learned from the film.

Other functions of the utilization officer include advising those con-
ducting training activities as to the kinds of film and other materials
that are available for their special purposes. This involves far more
extensive activity than can readily be imagined by anyone who is not
familiar with the vast range of naval training activities, including at
present many hundreds of different establishments.

If any of you could sit at certain desks at the Navy department,
and hear the telephone ring, and answer telephone calls from high
ranking officers attached to important ships of war, demanding pro-
jectors and films for those ships on an urgent basis, you would realize
that the fighting Navy is convinced of the value of training films.
That value, to the Navy, is increasingly based upon an intelligent and
comprehensive conception of the kinds of film desired, their appli-
cation to the subject, and the conditions and circumstances under
which the subject will be taught.

PROBLEMS IN THE PRODUCTION OF U. S. NAVY
TRAINING FILMS*

ORVILLE GOLDNER**

Summary. — The organization of the Training Film Branch and the scope of its
job are indicated. Problems encountered in the production of the Navy's training
films are considered. Special emphasis is given to research, pre-planning of pro-
duction and script writing. The difficulties that result from undertaking an extensive
training-film production program under wartime conditions are presented briefly.

Slide-films and motion pictures for the Navy are being produced
under the supervision of the Chief of the Bureau of Aeronautics, who
was directed by the Secretary of the Navy, in August, 1941, to
"... fulfill the photographic requirements of education and training
in the naval service." The Photographic Board, which made the
original recommendation on which the Secretary acted, lumped the
responsibility for the photographic requirements of education and
training with other photographic responsibilities and assigned them
all to the Bureau of Aeronautics because of its long-time experience
in naval photography.

As a result of this directive, the Photographic Division of the
Bureau of Aeronautics, through its Training Film Branch, serves the
entire Navy in its film production program. Requests for film
productions originate from training officers in the various naval
training centers maintained throughout the country, or from officers
in the training divisions in Washington. Requests come to the
Bureau of Aeronautics via the Bureau of Naval Personnel, which has
responsibility for all naval training. There are, however, two ex-
ceptions to this. They are the requests that originate in aeronautical
activities and those that originate in the Secretary's office. These
requests come to the Chief of the Bureau of Aeronautics and are
forwarded to the Training Film Branch via the Director of Photog-
raphy.

* Presented at the 1943 Spring Meeting at New York, N. Y.
** Lt., U.S.N., Training Film Branch, Photographic Division, Bureau of
Aeronautics, Navy Dept., Washington, D. C.

146

U. S. NAVY TRAINING FILMS 147

When production requests are approved by the cognizant authori-
ties, the Training Film Branch assigns a two-man team to work with
the technical advisor in outlining and producing a training film on
the subject. One team member is the educational consultant, the
other the project supervisor. Essentially, the project supervisor is
the coordinator and administrator of the project for the Navy.
Besides contributing the film ''know how," he activates the project
through his liaison relationships with the several persons jointly
engaged in it — the technical advisor, the Navy or commercial pro-
ducer, the educational consultant, the procurement and cataloguing
departments of the Training Film Branch.

The educational consultant helps to insure that a film, as planned,
teaches. He not only defines a film's purpose but helps to plan it
according to well established pedagogical principles. He finds ways
to fit it into existing curricula and may assist in adapting existing
curricula to the new instructional program. In several instances it
has been found that pictures have forced realignment of existing
curricula.

Since the organization of the Branch charged with responsibility
for producing films for the Navy (July, 1941), the total number of
projects completed is 1692. Of these, 1412 were slide-films and 280
were motion pictures. The total number of projects in production
at this time is 1296, of which 850 are slide-films and 446 are motion
pictures. Requests for production of films on additional subjects of
interest to Navy training are coming in at the rate of 200 a month —
clear evidence of the Navy's interest in the medium.

Another line of evidence showing the Navy's dependence upon
training films is found in the film distribution figures. In the last
quarter, over 90,000 prints have been distributed. Nearly one
thousand individual activities have been served. These include both
ships and the nearly five hundred schools and naval training estab-
lishments ashore where men are trained before being assigned to the
fleet or to which they are returned for further training after some
fleet experience.

The training films the Navy makes and uses have been designed
to be used in classrooms at the time in the course when they will help
the instructor to standardize operations and make ideas clear to his
students. They are not made to be shown as separate, uncorrelated
features. And when planned for one specific group, as is most often
the case, they are not expected to meet the complete needs of another

148 O. GOLDNER [J. S. M. P. E.

group being taught things in a different way. For example, slide-
films designed for use in the Aviation Service Schools for training
enlisted men in maintenance and repair of airplanes have not been
found particularly helpful for training civilian personnel in the
Aviation Assembly and Repair Shops, even though both groups are
working on the same model of airplane. The films the latter need
are definitely job-analysis films on assembly and sub-assembly of
parts, much too detailed to be of use in the Service Schools. The
purposes served in each are different, and hence the training aids
must of necessity be different too.*

It is our task continuously to analyze the problems peculiar to and
characteristic of every training situation. Training films must fit.
Simply, they must assist in training or they are an expensive waste of
time and strategic material.

We find it necessary to repeat frequently that we are not in the
business of making films per se; we are in the business of making
training aids. That is why in a training film program like the
Navy's there is no place for the movie making prima donna. Cellu-
loid fever is easy to get, but the making of effective training materials
requires analytical, straight-line thinking, planning, and execution.

When an official request reaches the Training Film Section, there
are still a great many questions that have to be answered before a
producer can be assigned to the task of producing the training film.
A thorough job of research and pre-planning must be done. Due to
the problems inherent in a training program during a war period,
basic research and pre-planning take on various aspects. First,
there is the research based upon standardized doctrine, good or bad,
realistic or unrealistic, which has been used over a long period of time
by a fairly well stabilized training activity. Second, there is the
research on a training program where there is no established doctrine —
where the whole training program is so new that a syllabus or simple
outline has not been developed.

Frequently it becomes the job of the Training Film Branch to
establish the doctrine along with the production of the training film.
In many cases, a training activity without established doctrine per-
mits the creation of a more effective training film than the activity

* The foregoing was written by Lt. Reginald Bell, U.S.N.R., Senior Educational
Officer for the Training Film Branch. It is reproduced here substantially as it
appeared in Visual Review for 1943. The remainder of the paper was written
by Lt. Orville Goldner, U.S.N.R., Officer in Charge, Training Film Branch.

Aug., 1943] U. S. NAVY TRAINING FILMS 149

that presumably has all its information frozen in outmoded hand-
books and syllabi. It is far more stimulating for the project super-
visor, the educational consultant, and the technical adviser to ap-
proach a problem that has not been thoroughly explored. A training
film that evolves out of such a situation is almost certain to be more
operational and less abstract than one that has been built out of a
maze of words and formulas.

If no technical adviser is indicated on a .request when it arrives
at the Training Film Branch, it is obvious that the Branch must
insist upon the appointment of a technical adviser before the basic
research on the training film project can begin. It is always hoped
that the technical adviser will come to the Training Film Branch
with two basic qualifications — first, that he will be a subject-matter
specialist, thoroughly experienced in the technical aspects of the
proposed training film; second, that he have sufficient authority
to make decisions that will hold and be approved by his bureau or
the activity which he represents. If the technical adviser happens
to be a desk engineer with years of experience or a technical writer
who has thought in terms of words and mathematics entirely when
considering his subject, he almost invariably creates many difficulties
for all those concerned in the production of the training film.

Let us consider for a moment the first type of research — that
based almost exclusively upon doctrine set forth in great detail in
handbooks and manuals. If the subject happens to be mechanics
or electricity or any one of a hundred other involved subjects on the
complicated apparatus of this war, in all probability, the authors of
the manuals and handbooks were engineers sitting at the desks of
the manufacturer of the equipment involved. It has been the
practice of the armed services for many years to buy with their equip-
ment instructional manuals that are supposed to contain the sum
and substance of all the problems involved in the construction, in-
stallation, maintenance, and repair of the equipment. Frequently
these have been considered all that is necessary for the guidance and
training of competent personnel. Needless to say, these handbooks
and manuals are generally one-sided — they tell the story about the
equipment that the manufacturer wants to tell. Constructed as
they are, in Detroit, Chicago, Cleveland, or other industrial centers,
miles from the field of operation in which the equipment is used, they
are unrealistic, verbose, and crammed with mathematics that only
thoroughly experienced engineers can understand. And yet more

150 O. GOLDNER [J. S. M. P. E.

than once, these engine encyclopedia, Diesel dictionaries, and radio
rhetorics have been given to training film officers as scenarios.
"Certainly," says the technical adviser, "what more do you want?"
"Just make pictures to fit, and you'll have a beautiful training
film." And, believe it or not, we've made a few along this line —
abstract talking panoramas to delight the eyes and ears of our best
engine Einsteins.

We have been speaking here of one kind of material that is pre-
sented as doctrine for the construction of training films. This is the
overcomplicated and unrealistic which makes picture planning
difficult. Another kind of material presented as doctrine is the
oversimplified — that kind that grew up in an unstudied training
program, in the hands of an alleged instructor who thought that
generalizations were enough. This kind of material contains pro-
found statements such as "Proceed to the engine, make adjustments
preparatory to starting, turn up fuel oil to the proper level, turn
throttle to recommended starting position, proceed as recommended
in Section C, p. 32 of the Manufacturer's manual, serial number 836,
etc., etc."

We who are involved in the construction of training aids for the
Navy know that neither of these kinds of material is sufficient as a
basis or plan for an effective training film. Our job of basic research
must go further. Consider for a moment the construction of train-
ing films on a series of large tactical problems which change from
day to day just as the war itself changes from day to day. The
movement, the pattern of strategy, the war equipment that won a
battle yesterday may not win the battle at some future date for which
we are building, and yet, we have to make training films on these
problems too. One such problem has kept us involved for over a
year. In that time, tactics have changed, equipment has changed,
and personnel has changed. Technical advisers who were considered
authorities when we began may no longer be considered authorities,
or they have been removed to fields of operation inaccessible to the
Training Film Branch, for every day, more men must go to combat
areas whether they are working on training films or not. It is safe
to say that within the year, typewritten material a foot thick has
been accumulated on this particular problem. Dozens of experts
have been consulted and countless maneuvers have been watched
for the purpose of accumulating authentic, operational data. There
must be continuous checking and cross-checking — for an error, made

Aug., 1943] U. S. NAVY TRAINING FILMS 151

real and in effect true by projection on the screen of the classroom,
could conceivably lose a battle if enough people believed it and
acted accordingly. Conversely, the truth projected and made real —
simply and operationally — might win the battle. It is this admitted
effectiveness that justifies the production of training films; in fact,
demands it.

Such a job of research and analysis is not .an easy task. It is
difficult enough to get a consensus on problems where standard
mechanisms are involved. It is overwhelmingly difficult to get a
consensus when broad tactical problems and intricate new machines
of war are involved. Often, much valuable time is lost in getting a
decision on a simple point, and these delays are not easy to overcome
or explain; for in the end, there is the project file in the Training
Film Branch which indicates that a certain training film has been in
production an inordinately long period of time. With a few projects
like this, the total production program is bound to look out of joint.
But the research, pre-planning, checking, and cross-checking must
be done.

The second research technique — that which is without benefit of
doctrine to begin with — is largely observational. The project super-
visor, educational consultant, and technical adviser travel to the
training activity that is to furnish the problem and the pattern for
the training film. A typical example would be the assembly of a
pontoon bridge. Let us assume that this is a new activity for the
Navy, that the pontoons are new, that the total job is a part of an
entirely new operation which extends the function of an established
Navy rating. On such a problem, the researchers scrutinize what
is going on. This may take a couple of days or a couple of weeks or
longer. It may mean a trip to the South Pacific or the Caribbean,
to one location or many locations. But inevitably, it means a de-
tailed analysis of work under many conditions. With the training
officer in charge, project personnel attempt to determine what tools
are best and what techniques are best for the job to be done, wherever
and however it must be done. The training film must, of necessity,
set high standards for this particular operation wherever it is shown.
Perhaps the training officer had never thought of his job in terms of
the best tools and best techniques; perhaps it had been done pre-
viously with whatever tools were at hand by whatever method
seemed most appropriate at the moment. Obviously, this is not
precise enough for the discerning eye of the camera. When a simple

152 O. GOLDNER [J. S. M. P. E.

wrench in use is projected on the screen, it may appear at once to
be either too large or too small, or badly handled. Unskilled and
indecisive workmanship and inappropriate equipment becomes read-
ily apparent when reviewed on the single plane of the classroom
screen. A recent example of this happened in a series of films being
undertaken by the Branch on the disassembly of a certain engine.
The two Machinist's Mates assigned to appear in the films were
thought to be thoroughly qualified for the job. Aboard ship in the
engine room, they could undoubtedly get by as able mechanics. And
yet, when the first sequences of the particular training film were pro-
jected, it became apparent immediately that these two men were
inept with tools and frequently used methods that could not be con-
sidered as standards for the training film. The sequences were re-
shot and the films continued with more experienced mechanics who
knew the proper tools and techniques. All this points to the fact
that research and pre-planning can not be casual if effective training
aids are to result, and further that the production of training aids
must not be considered as a manufacturing process in which one
film formula is the skeleton over which a wide variety of subject
matter can be stretched. Whenever this happens, the formula
becomes more important in a teaching situation than the subject
matter it purports to present. Training films designed on this
pattern are inevitably soporific and can not help but defeat the
purpose for which they are intended.

What does the Training Film Branch do after the research and pre-
planning on a given project are considered finished and approved to
a point where production may be started with safety ? A qualified pro-
ducer must be selected. Scripts must be written; a location or
locations must be prepared. Personnel and material must be
allocated. These and a myriad of other jobs are next in line.

And all this must be accomplished in some order while the Navy
and the nation are at war. All this must be done without stopping
the flow of men and equipment to the battle front, without taking too
much of the valuable time of technical advisers who are at the same
time preparing themselves and others for actual contact with the
enemy. All this, like research, is not easy. Every step of the way
is fraught with problems. There is always the problem of priority.
Who shall be first and what project? When everything is needed
now and urgency is the order of the day, there still must be some
plan — something first and something second — when the time of

Aug., 1943] U. S. NAVY TRAINING FILMS 153

leaders and the allocation of facilities are considered. Then there
is the problem of security. The Navy's equipment and plans have
to be protected vigilantly day and night, for the enemy is ever pres-
ent and alert. How is it done? Many of you are producers work-
ing for the Navy and you know. It is sufficient to say that it is
done, slowly, continuously, meticulously. It is tedious and time-
consuming for you and for us, but when the safety of the nation is at
stake, it is only wisdom to be hyper-cautious.

Let us examine critically some of the steps in actual production.
What of script writing? It should not be necessary to labor the
point that a training film is not like a theatrical film and not for the
same purpose, and not for an audience with the same mental set.
Neither is a training film like a newsreel which cuts quickly from
subject to subject accompanied by a commentary which on analysis
says nothing but says it well and with so much seeming authority.
Each type of film has its place in our culture, but one can not be sub-
stituted for the other in a training situation. Yet, many of the
writers of the Navy's training films are hard to convince of this fact.

The writing of a script for an effective training film requires first
of all the ability to penetrate the obvious and the loosely accepted
truths in a given situation. It requires persistence and a prying
curiosity. It requires incisiveness and straight-line thinking, and
with it all, the ability to put it on paper in acceptable English with
an economy of words. The writer of a training film script must, of
necessity, have a vivid imagination. He must be picture-minded
first and word-minded second. In analyzing his subject matter, he
must ask himself constantly, "What is the picture at this point that
will tell the story in terms of the objective?" And, having deter-
mined the picture, he must then ask, "What is the simplest mean-
ingful statement that I can make that will extend the effectiveness
of the picture and add to its retention potentiality?" The writer
with genuine ability for training film production understands that
he is working with a medium in which the primary value is visual
and the secondary value is auditory. He knows that he is not writ-
ing lectures with pictures "to fit" ; he is organizing pertinent pictures
of subject matter in movement, using the fewest possible words to
describe, to emphasize, to extend.

Does the Training Film Branch get what it wants in the way of
scripts for its films? Frequently it does, but time after time it does
not. There is much revising, much compromising, and occasionally

154 O. GOLDNER [J. S. M. P. E.

the accepting of the obviously bad in the name of urgency. Gener-
ally, no one can be blamed for the inadequacies. Perhaps, in spite
of all research, sufficient data were not available to give continuity
to the picture plan. Perhaps certain pictures were known to be un-
obtainable and without them the plan would have blind spots.
Then again, perhaps, there had been insufficient experience with a
given piece of equipment to furnish the facts about a certain opera-
tion.

However, there are times when script shortcomings stand out as
direct evidence of the writer's refusal to accept the training film as a
special instrument with a special purpose. When writers insist upon
using pictorial cliches at the beginnings and ends of all training films,
it becomes obvious that they do not know how to begin and how to
end the film in terms of the objective originally set forth. It points
to a limited concept of the job to be done and a definite lack of
ability to work in the film medium. Words can not describe the
fatigue that comes from going to the projection room and seeing film
after film begin and end with the opticals made up of the same
twenty-five best stock shots of ships plowing through the waves, big
guns shooting at nothing, and planes peeling off, accompanied by
ominous words in sepulchral tones on the scope of the war and the
size of the job and the beauties of Democracy and the beating we are
going to give Hirohito, etc., etc. And we must not forget, indeed,
can not forget, the overloud, strident music that fits the film the way
ice cream goes with dill pickles.

The writer may not wish to take credit ior all this, but he sets the
pattern — good or bad — and the director, the cameraman, the editor,
cutter, and narrator all follow the line.

Photography itself is probably the least of our problems. Most
cameramen are able to get some kind of image on the film. Inas-
much as a large part of the shooting of training films must go on in
spite of weather conditions and countless other limitations, it is
generally necessary to accept photography that is adequate, rather
than good. To insist upon photography that is the best possible
under ideal conditions in a given situation would often delay projects
beyond reasonable limits.

Producers who work on training films for the Navy are always con-
scious of the demands for close-ups, for better definition, and maxi-
mum depth of field. These are essential in operational training films.
Of great importance also are the orientation and re-orientation shots

Aug., 1943] U. S. NAVY TRAINING FILMS 155

for which the Training Film Branch asks over and over again. A
training film that skips around over an engine or a ship or anything
else with close-ups and medium close-ups is certain to lose and con-
fuse the trainee. He must be orientated to the problem in the be-
ginning, and must be re-orientated at intervals throughout the film.
This orientation must be operational; that is, it must be from a
position in which the trainee would find himself if lie were working
with the real thing in a tactile relationship. Frequently, effective
orientation shots are not possible in live photography, and it becomes
necessary to resort to diagrams or other pictorial devices. Any de-
vice is legitimate if it achieves the purpose for which it is intended.
Here again, like all the other complicated aspects of training film
production, the photography is right when it gets to the screen the
cogent picture information that the training situation demands.

It is not necessary to have beautiful clouds in all exterior shots
and to have every Diesel mechanic backlighted in close-ups to make
him glamorous, but realistic esthetics have a place in training films.
The cameraman who understands his medium, who uses his camera
creatively and not like a garden hose, can combine on the screen the
document of an activity in a composition of values from white to
black that adds immeasurably to the value of the film and the pleas-
ure of the audience.

Considerable time could be spent on other subjects as they relate
to the production of training films. These include music, color,
animation, sound effects, narrators — their voice quality and de-
livery— and the subtle but emphatic values of the great range of
screen devices. There are others, but they are beyond the scope
of this paper.

In conclusion, it seems necessary to say a few words about the job
that confronts us jointly — you, as civilian motion picture engineers,
technicians, and producers, and those of us in the armed services as
technicians and educators working on the production of training
films.

We have a war to win. There is much to be done before we win it
and bring it to a victorious climax. Every effort we make must be
to that end. Each has a job to do, and ours is training men to be
more effective, with less danger to themselves, in some phase of this
intricate bloody struggle. One of the media we are using for this
training job is the motion picture.

How can you help more ?

156 O. GOLDNER

By studying with us the bottlenecks that are keeping all of us
from being as effective as we should be. There are the bottlenecks
in animation, in laboratory work, and in optical work. You can
help by analyzing the facilities, the equipment, and the processes
involved. Certainly, there are ways to improve all three. There
must be ways to turn out more of a better product, faster.

We can look at the work being accomplished for the armed serv-
ices by all the facilities of the motion picture industry with con-
siderable satisfaction. But, in terms of the job to be done, we must
look to the future with an expanding concept of the function of the
motion picture and a more profound understanding of its value as
a training instrument.

THE 16-MM COMMERCIAL FILM LABORATORY'

WM. H. OFFENHAUSER, JR. **

Summary. — Several years ago J. A. Maurer reported1 upon the graininess of
direct 16-mm prints in comparison with reduction prints from 35-mm negatives.
Somewhat earlier'2' he reported upon the status of direct 16-mm sound in comparison
with sound optically reduced from 35-mm to 16-mm. The comparisons appeared
so favorable to 16-mm that the next step was to put the procedures into commercial
use. This paper describes the methods and the machinery used for the purpose.

It was necessary to standardize laboratory and film-handling; all picture printers
are of the slow-speed step-contact type,, all use the same type of lamp as a light-source.
All sound printers are of the optical type; all use the same type of lamp and the
same type of ammeter for control. No contact sound printing whatever is used, due
to the very serious losses that result from such printing.

It was found that one — and only one — raw-film material should be used for each
operation — the material with the best resolving power. Fortunately the material
with the best resolving power has the other necessary desirable photographic charac-
teristics. Eastman 5203 was selected as the duplicate negative material. Dupont
605 was chosen for the release print raw stock; Agfa 250 for the original sound
negative material. Kodachrome was found to be the best available material for
original 16-mm films, not only for color duplicates but also for black-and-white
fine-grain release prints as well.

It was necessary also to standardize inspection equipment, especially sound
equipment. A film-phonograph of excellent film motion with a 0.4-mil slit image,
a noise-free amplifier, and a two-way loud speaker system of the horn and direct-
radiator type, with a standard 400-cycle cross-over network, is used for the inspection
of 16-mm sound negatives and sound prints that are used for further duplicating
(for example, prints used for Kodachrome duplicating). The overall electrical
characteristic of the system is similar to that of metal diaphragm systems specified
in the "Revised Standard Electrical Characteristics for Two-Way Reproducing
Systems in Theaters" issued in 1938 by the Academy of Motion Picture Arts &
Sciences. For combined print inspection, Bell & Howell utility projectors adapted
to connect into the system used for the film-phonograph were found the best commercial
compromise.

Uniformity of product is readily obtained; permanent records of each piece of
film processed are sufficiently complete to permit the duplication of results long after
the details of a particular job are forgotten. With but one variable in each significant
step of the process, errors in processing are quickly traced and corrected. Maximum

* Presented at the 1942 Fall Meeting at New York, N. Y. ; received March
15, 1943.

** Precision Film Laboratories, Inc., New York, N. Y.

157

158 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

uniformity is achieved simultaneously with maximum output; the methods described
are well suited 10 mass production.

In discussing the 16-mm motion picture film laboratory and its
commercial operation and practices we shall ignore in this paper time-
consuming and attention-diverting frills such as fades, wipes, dis-
solves, and whirls, and concentrate entirely upon the operation of a
laboratory in relation to the thought content and purpose of the
films to be produced. In war nothing can be condoned — much less
encouraged — that does not directly contribute to the accomplish-
ment of the desired purpose.

What is the primary purpose* of a 16-mm film laboratory, or for
that matter, of our 16-mm industry, now that we have been engaged
in war for the larger part of a year? No one who is familiar with the
facts can honestly include pure and simple entertainment and blatant
advertising; there is but one real objective: training and its related
films dedicated to the job of making training of ever-increasing scope
available to an ever-expanding group of our trained citizens, and to
make our methods more effective from the standpoint of saving time
and improving the quality of instruction.

At the Fall Meeting of the Society three years ago at New York,
this identical statement was made in an appeal for the production of
business films for internal use;3 in today's language, training films.
The fundamental requirements of a good training film program now,
as then, remain essentially the same as reported by the Luchaire
Committee on Intellectual Cooperation of the League of Nations in
1924:

(1) Slides and motion pictures should be used for maximum
effectiveness. As a general rule, the use of these two adjuncts is
not judicously proportioned, one often being used to the complete
exclusion of the other. We can no doubt agree that the conclusion
of eighteen years ago is still valid today; too many projects use but
one medium to the complete exclusion of the other.

(2) All objects and scenes that the audience is intended to watch
and remember in movement should be shown in movement. Still
pictures representing objects and scenes that ought to be seen in
movement should be banned, as giving a distorted impression of the
actual facts. Our films are much improved in this regard although
we still find instances where stationary objects are photographed

* This paper does not take into account the 16-mm prints of entertainment
films furnished by Hollywood to the Armed Forces.

Aug., 1943] COMMERCIAL FILM LABORATORY 159

with a motion picture camera and moving objects with a still camera.

(3) The screen can not displace the personal element; it can to
some extent displace printed matter, and it should, in all events, be
used in combination with it. The use of the screen in conjunction
with text-books and printed matter is still quite undeveloped; its
effectiveness when properly used is in the top rank of communication
media. "Nuts and bolts" pictures especially can take advantage
of this pedagogically correct instructional technique.

(4) The screen should be used in combination with personal con-
tact in "getting the idea across." It should be used at the location
where the teacher ordinarily operates whenever it is of advantage to
do so. It should be possible to repeat the picture several times if
necessary; the picture should be definitely constructed in such a
manner that it will bear repetition. A really well made film can be
run at least five or six times before it begins to seem dull.

Training practice has shown a tendency to bring the screen to the
student instead of the student to the screen. This tendency is in the
proper direction and, fortunately, is steadily growing.

It is not true, however, that films are always constructed in such a
manner as to bear repetition, as is particularly necessary in films for
instructional purposes. Too often a large number of diverting
technical effects such as fancy wipes, dissolves, and the like have
been used in a single reel. Such technical effects do not cover up the
glaring defects in plot, continuity, and lack of logical presentation
that are also usually present. Our technical effects wherever used
shall aid the story, not "steal the show."

(5) The screen can not be used in the proper manner unless there
is very wide distribution of effective up-to-date apparatus so that
each teacher, of even small classes, can have his own projection equip-
ment. The simplest apparatus to handle consistent with complete
technical adequacy will be best. If the screen is to do its proper
work, the apparatus must quickly become a thing in daily use.

On the whole, current commercial 16-mm sound projectors (and
this includes those being currently purchased by the Government in
quantity under the most strict specifications), while quite satisfactory
in most particulars, almost invariably have the following inadequate
or poorly designed features :

(a) The Loud Speaker.* — Present flat baffle types are hopelessly inadequate
for high-quality reproduction. For semipermanent installations an efficient
horn-and-cone combination such as the Jensen speaker, supplied under the

160 W. H. OFFENHAUSER, JR. [J. S. M. P. E.

Bell & Howell trade-name "Orchestricon," is quite suitable. For semiportable
use, a reflex -type horn of reasonable efficiency and frequency characteristic such
as the Jensen "Hypex" is quite suitable. The loud speaker should be designed
to cover with sound the area to be served by picture.

(6) Sound Optics. — Present machines (except only the Eastman Kodak)
use sound optics of inferior resolving power providing very coarse projected slit
images; a width of not greater than 0.5 mil is necessary for good-quality 16-mm
sound reproduction. On the best of other machines, the slit width is twice as
wide as that recommended, 1.0 mil.

(c) 2-Inch Picture Projection Lenses.6 — About 70 to 80 per cent of the pro-
jectors in use should use a projection lens of this focal length; unfortunately all
lenses of this focal length of wide aperture (//1. 6) made without field flatteners
have very poor resolution in the corners and very bad field curvature. Only
one manufacturer (Eastman Kodak) regularly supplies all 2-inch lenses with a
field flattener. The field curvature and poor resolution in the corners still persist
in 2-inch lenses of smaller aperture although in some cases not to as great a
degree. U. S. Army and other Government specifications have sought to get
around this problem by specifying lenses of 3 -inch focal length which, at smaller
apertures, show less field curvature. While there is an improvement in flatness,
the focal length is definitely wrong for the average application as judged by the
criteria of the Non-Theatrical Committee Report of July, 1941 ;6 the projected
image is too small and the perspective incorrect.

(d) No Provision for Proper Focusing of "Non-Standard" Emulsion Position
Prints.1 — Most projectors have no provision whatever for refocusing sound
optics for Kodachrome duplicates. This results in tubby, noisy, and unintelli-
gible reproduction from even excellent films. Eastman Kodak is the only
manufacturer that provides sound refocusing as standard equipment on any
standard projectors; Bell & Howell provides this feature as optional equipment
at extra cost. Since there is almost a 10 to 1 cost ratio between cheap black-
and-white prints and good -Kodachrome duplicates, it seems an anomaly to
provide the better reproduction for the cheaper film. No manufacturer makes
any provision for adjustable pre-set stops for refocusing picture of Kodachrome
duplicates when changing from standard to non-standard-position films.

(e) Lack of Accessibility for Proper Cleaning. — This is a most important
feature, universally recognized in 35-mm theatrical equipment and universally
ignored in 16-mm projectors. In particular, there is not one widely distributed
sound projector on the 16-mm projector market that has a readily removable
and properly cleanable picture gate, although practically every 35-mm projector
made in the last 20 or more years has had this feature.

(6) The mode of use of the screen must be improved, having
regard to the fact that it can act upon the mind of the spectator

(a) By faithful presentation of the subject.

(6) By the representation of the subject simplified.

(d) By the representation of the subject intensified, magnified, speeded up,
slowed down, built up by degrees, or superposed.

Aug., 1943] COMMERCIAL FILM LABORATORY 161

These different methods must be employed according to a logical
scheme, taking into account the subject to be dealt with and the
specific character of the audience to which the film is planned to be
shown.

For training films it is of utmost importance that the exhibition
and use plans for a film be fully completed before the first camera
exposes the first foot of film. Maximum effectiveness presumes the
gearing of the subject matter of the film to the audience.

(7) The screen is a valuable means of suggestion; it will be used
as a time-saver, often a valuable one, in putting across all matters
that depend largely upon visual memory.

The lighted screen in the darkened room compels concentration
upon the material presented. It is not only possible to put across
details of mechanisms and their operation, but also to explain the
coordination of activities that can not in the usual course of events
be directly observed. This field is potentially a very productive one
for industry as well as for our Armed Services.

(8) In order to economize effort and to save expense in making
films, and to derive maximum profit from them, it is advisable to
decide definitely beforehand to what extent regular photographing
and animation are, respectively, to be used. Due to the high cost of
animation in comparison with regular photographing, animation has
been used to a much smaller degree than in many cases seems de-
sirable for maximum effectiveness; however, films made in the last
year have shown a definite improvement.

THE THREE-YEAR INTERVAL FOR THE 16-MM COMMERCIAL LABORATORY

The 16-mm commercial film laboratory has "cleared decks" in the
past three years; in order to make way for a large volume of high-
quality prints in Kodachrome and fine-grain black-and-white film it
has eliminated all extraneou,s activities. It no longer prints 35-mm
Kodachrome or black-and-white slide-films; it develops no 35-mm
film and makes no 35-mm prints whatever. The precious production
capacity formerly taken up by this variety of activities is now de-
voted entirely to 16-mm high-quality print production. Needless to
say, this action has made it possible to increase greatly the output
per man-hour and per dollar, and with a material improvement in
technical quality. In the case of Precision Film Laboratories, it is
possible to take any production print and project it with theatrical
satisfaction with a technically complete arc projector upon a 12-ft

162 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

screen; not only the sound but also the picture will be of theatrical
quality. And it should be so; the inherent resolution of today's
best materials with proper handling is entirely adequate by present-
day standards.

PRESENT-DAY 16-MM FILMS

The majority of 16-mm films processed today in the 16-mm com-
mercial laboratory are of the training or educational type which are
taken silent and use an "off-stage voice" or commentary sound-track
rather than synchronized sound. Since we are a nation at war,
large numbers of prints are needed from each subject — and simplicity
and speed are the keynotes in the production of these direct and
to-the-point films.

The Original Picture Film. — Sixteen-mm originals are usually
direct positives; either black-and-white reversal or Kodachrome.
These direct positive materials are almost ideal for the job at hand.
The dirt and scratches usually accumulated in usual careful handling
are quite objectionable when negative is used as the original ma-
terial. In direct positives, however, these imperfections are prac-
tically invisible and splices do not show. The intermediate negative
and print (for black-and-white) permit an almost infinite number of
high-grade black-and-white prints that are not only appreciably
superior to 35-mm optical reductions as to graininess, but also far
better as to softness and gradation due to the use of the negative-
positive process in obtaining the final result. The advantages of
direct positive materials are now so pronounced that negative-type
materials have been practically eliminated in all applications where
a large number of copies is required.

Direct positive materials are not ordinarily developed by com-
mercial film laboratories; since the cost of developing is included in
the price paid for the film, developing is under control of the film
manufacturer. This applies to reversal materials as well as to
Kodachrome. Some independent laboratories are reversing positive
film but the volume of this class of work at the present time is not
large.

Materials. — There are two kinds of original Kodachrome available,
"Regular" (which is intended for use in daylight) and Type A (which
is intended for use in artificial light). The prime difference between
the two is that if both are projected with the usual high-efficiency
tungsten lamp, the color will appear correct as seen by daylight for

Aug., 1943] COMMERCIAL FILM LABORATORY 163

the Regular film and as seen by highly overvolted Photoflood No. 1
or No. 2 lamps for the Type A. Since the blue-sensitivity and the
green-sensitivity of Type A are higher than that of Regular, while
the red-sensitivity is nearly the same, it is easier to use Type A with
a filter in daylight than to use Regular with a filter in artificial light,
as the calculated speed of the Type A film so used does not appre-
ciably change Another advantage of Type A used with a filter in
the outdoors is that the film is not subject to "haze trouble" caused
by excessive ultraviolet and blue- violet. With proper color-tem-
peratures, however, it is best to use Regular for daylight and Type A
for artificial light.

Present-day reversal materials still give the impression that they
are intended for the amateur who, according to a current fallacy,
likes his film as fast as possible and as "hard as nails." In original
reversal materials today, there is still a big need for a low-contrast,
long-reproduction-scale material, since there is no such material on
the photographic market and we have been struggling along without
it for some five years. Agfa did manufacture a film called "Old Type
Superpan" which was a long-scale material of beautifully low con-
trast, but it was unfortunately withdrawn from the market when
the faster emulsions of the "Supreme" type made their appearance.
The film manufacturer who supplies such material and incorporates in
it the new emulsion improvements of the last five years as to grain
reduction and speed will not only earn the blessings of a long-suffering
professional market by reopening wide fields of usefulness but also
should find it very profitable as well. All finer-grained reversal
emulsions available today are of the high-contrast type.

Today's Compromise. — Critical professional film users have been
aware of this situation for the past two years or more and have
turned to Kodachrome as the original material for their black-and-
white prints. Kodachrome has appreciably lower contrast than any
finer-grain reversal film at present on the market, and in the opinion
of its users, is well worth while despite its higher cost and lower speed.*
From a production viewpoint its slower speed is a serious handicap
due to the appreciably larger amount of lighting equipment necessary
to photograph with it. It must be remembered that the mobility of
the industrial camera is measured by the mobility of the lighting
equipment required to illuminate the subject.

* See Appendix for further data.

164 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

The Work Copy. — The first step in handling developed direct
positive originals is to make the usual work-print or editing copy.
Basically, there is little here to describe except that the work-copy
actually made depends primarily upon the functions it is to perform.
It may vary all the way from a one-light copy made on positive
stock and developed in a positive bath (with a negative viewing
aspect) to a Kodachrome duplicate intended to show reasonably
closely the color balance to be expected in the release duplicates.

One extremely important point should be made : while it is true that
a beautiful photographic copy is not ordinarily required of a work-
print, it is equally true that a cheap work-print may be the most
costly element in the whole production process. If the original is
scratched by careless handling or by printing in an improperly de-
signed or maintained printer, all the effort made to obtain an other-
wise excellent original is futile. Careless handling of originals during
the work-print and editing stages have been a major cause for what
might be called the high mortality rate of otherwise good films.

Both work-print and original picture are returned to the film
maker; the next job at hand is the editing of the picture and the
preparation of the sound-track. Generally speaking, the commercial
laboratory does not edit film, as its function is to perform the essen-
tially mechanical work of the copying process without attempting
to do any "creative" work whatever.

The Sound Negative. — After the work-print is edited, sound is
scored. While sound is recorded as a negative as in 35-mm, here
again the procedure diverges widely. Sound is recorded upon
yellow-dyed high-resolving-power film exposed through a blue
filter; ultraviolet is undesirable as it causes inferior resolution. The
harmonic distortion with an 85-per cent modulated sound-track of
400 cycles of density 1.5 can be kept as low as 1 per cent; with ultra-
violet light and usual ultraviolet-type film-stocks in the same ma-
chine, it is difficult to get the distortion down to 6 per cent. The
improvement in noise level of yellow-dyed film is likewise satis-
fyingly large. (Recently blue-dyed films have been introduced
whose performance characteristics seem to be quite similar to those
of the yellow-dyed film that has been in use for the past three or four
years.)

The laboratory develops sound-film at standard time (which
happens to be 6 minutes) for the standard negative density of 1.90.
As accurate and complete control is essential to consistent high-

Aug., 1943]

COMMERCIAL FILM LABORATORY

165

Tape To Can Which This
Log Describes

From

SOUND LOG SHEET
To

Date:.

Page No.:....

PRECISION FILM LABORATORIES

21 W. 46™ STREET
N«w YORK, N. Y.

(Ctj «•<» Sute)

Ordered By

Sound Man

Order Number „

Microphone Man

Title of Film.

Location :

Cameraman

Film: Make:.... Emulsion and Coating No.:
B-M Recorder Type No.: Serial No.:,..._..

Winding
Lamp No.:

£* Direction £* J
Filter:..™ „._

B-M AGN Amplifier Type No.: Serial No.: Current:

B-M Recorder Amplifier Type No.: Serial No.: Cum

B-M Power Supply Type No.: .' Serial No.:

Microphone: Name and Type: Setting: R — D — C

Decrease

Filters: Low Pass Type No

Serial No.: .

.Others:

Take
No.

•&T

Fs0r

Scene
Seconds

cTent

Mike
Setting

Main Gain
Setting

o,SNon.

REHAUU

Exposure
Test

INSTRUCTIONS TO LABORATORY: Develop test (last feet on outside of roll) at standard time. Develop track accordingly;

INSTRUCTIONS TO LABORATORY: Develop test

. . ,. .... , , Black and White

this film will be used for ^^

Test Dev. Time: Test Density

Please fill in and return original to _

Film Dev. Time:

..Average Density.™ „_..

, ; retain copy.

FIG. 1. Sound log sheet.

quality results, all information transmitted between laboratory and
film-maker is in writing. A typical sound log sheet is shown in Fig.
1. Comparable log sheets are made for picture; these too are sent
to the laboratory to give the laboratory an opportunity to suggest
improvements in lighting and similar matters of camera technique.

As part of the inspection routine, every sound negative is com-
pletely run and inspected at synchronous sound speed on a 16-mm
film-phonograph and reproducing system having a 16-mm frequency

166 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

response characteristic quite like that of the Academy of Motion
Picture Arts & Sciences standard 35-mm characteristic as described
in the Technical Bulletin of October 10, 1938. The film-phonograph
fulfills the requirements of such standard reproduction; it uses an
optical system with an 0.4-mil slit produced by a microscope ob-
jective together with an 8-volt, 2-ampere exciter-lamp to provide the
necessary mechanical rigidity of the filament to avoid microphonic
noise. The exciter-lamp, together with the heaters of amplifier
tubes operated at low level, is energized from a rectified power-supply
to assure satisfactorily low noise and hum content. The amplifier
drives a 2- way "horn-woofer" loud speaker system utilizing a con-
ventional 400-cycle, 180-degree cross-over network. Needless to
say, the combination is of better than theatrical quality, as is neces-
sary in equipment to be used for judging sound quality critically.

A report of the inspection is sent to the customer, and, if indicated,
methods of correcting difficulties and improving quality are sug-
gested. If the recording is below par, the customer is advised to
make a retake. Under usual conditions, the need of retakes is rare.
It is interesting to note that distance from the laboratory is no
measure of the quality of the resultant product ; the great bulk of the
exchange of information is arranged by mail ; some of the finest work
is turned out by film-makers located on the other side of the conti-
nent as well as by those within a stone's throw of the laboratory.

The Sound-Track Print. — After the negative has been approved, a
sound-track print is made for checking purposes. This is in every
respect the highest-quality sound-track print that can be turned out,
as the quality of the release film is judged by this print. As in the
case of all other 16-mm prints, it is made on fine-grain film.* It has
been found impossible to make good sound-track prints with a con-
tact printer; accordingly, all sound prints— both combined prints
and sound-track prints — are printed on a one-to-one optical sound-
printer whose slip with acetate base films is even less than the com-
parable 35-mm "slip" of high-grade non-slip printers with nitrate-
base films. If we can judge by the papers in the JOURNAL, the sound-
track printers for Fantasia were of the general type used for 16-mm;
this type of printer had been in use for 16-mm printing for several
years before the Fantasia equipment made its appearance.

The sound-track is then projected on the film-phonograph equip-

* Technical Appendix.

Aug., 1943] COMMERCIAL FILM LABORATORY 167

ment just as was the negative. The same man who checked the
negative usually checks the print. While cases of defective sound-
prints have been almost unknown for the last year, track-prints are
still carefully checked, as they are often used for Kodachrome dup-
licating or for re-recording. Fig. 2 is a typical "pink" sheet, as we
call our Technical Record Sheet. Fig. 3 shows the reverse side of
the "pink" sheet; as will be noted, very little is left to the imagina-
tion when defects are described.

A PRODUCTION EXAMPLE

Assume that the job to be done is making Kodachrome duplicates
at the same time black-and-white fine-grain prints are to be made.
The film-maker ships to the laboratory the original edited Koda-
chrome, his Kodachrome work-print, the sound negative, and the
sound-track print. These are accompanied by specific instructions
concerning the reproduction required in key scenes.

Preparation. — The film is turned over to the Preparation Section,
where it is first inventoried and then prepared for printing. This
includes checking the marking and identification of the leaders and
the inspection of splices and the checking of emulsion positions. As
this work is the function of the film-maker and not of the laboratory,
the film is returned to the film-maker for correction if incomplete
in a major degree; if incomplete in a minor degree, the laboratory
will, upon authorization, perform the necessary work. In the
Preparation Section, the timing sheets for printing are made ready —
and made to correspond with the identification leaders on the original
films.

Sound Inspection. — The sound-negative and the sound-track print
are turned over to the Sound Inspection Section and checked against
the original recording log sheets and laboratory processing records
("pink sheets"). Since both sound-negative and track-print will be
used for printing (one for black-and-white and one for Kodachrome),
both are carefully checked to make certain that the film is in prime
condition and that the sound is up to par. Both are then returned
to the Timing Section with the report of their condition.

Timing of Picture. — The Kodachrome original is turned over
to the timer; the procedure in timing Kodachrome is quite
similar to that used in timing black-and-white. The timer de-
termines the filter combination required, and enters this and the
scene lights on the timing sheet. A pre-perf orated timing strip is

168

W. H. OFFENHAUSER, JR.

[J. S. M. P. E.

TECHNICAL DATA

PRECISION FILM LABORATORIES

INVOICE DATE

J L

GATE RECEIVED

CUSTOMER'S ORDER NO

OUROROCRNO

TERMS. NET CASH

Date Wanted-

REEL NO

SUBJECT

ttU&

FOOTAGE

OF STOCK

REMARKS

S m/m O Negative D Hold D B. & W. Q

•(SUITS Of TBTS

35 m/m D Positive Q *«»""• D Color D

Reversal G Picture D Sound D Combined D

First Print

Subsequent Print

Special

Picture Printer # Emul # Weston

Contact fj

Rheo. Setting Iris Setting F"Jr |

Optical 1:1 n

Of. Ola.. 1

Valt Watt Lamp Used At Volts

Reduction Q

Head To Tail D Tail To Head Q

Sound Printer •#• Set At Ampere With

Filter Emul J '« D

VA PI White Li9ht D Negative Emul.

H. to T. D T. to H. D

L-J UG? n Negative Density

Print Density Detirwl

YD D BG12 n

Printed By

Machine No. Dev. Time Bath ( p«

«"• n Gamma

REMARKS J»"

Ml»« D

Bath

ci»l.- D
Developed By

Picture Density ) ^ D Track Density Read _

Quality)^ D

REPORT

(r«r n

Date

Inspected By

C" ) f ro D KEMA'"(S

Date Released

U^D ;U~bK

Released By

fc| REMARKS

Date

Incomplete Q

FIG. 2. "Pink sheet."

then made up from the timing sheet. Since Kodachrome is printed
under a weak green safelight, it is necessary that all operations to be
performed in the printing shall be done by automatic means to
assure certainty in the result.

Sound Inspection of Originals. — It the meantime, the sound-nega-
tive and the sound-track print have been prepared and checked for

Aug., 1943]

COMMERCIAL FILM LABORATORY

169

PICTURE

SOUND

DEV.

ORIG. PRINT

OEV.

ORIG. PRINT

DEV

ORIG. PRINT

DEV.

OK 1C

Fogged

~Ef "

D G

Oil Spots

D D

Scratches

D a

Water Spots

D n

Long D Int. Q

Dirt

D n

Short D Steady G

Soiled In Handling

G G

Cinch Marks

{•

{[

11 {I

Reticulation

G G

Finger Marks

•
i

(I il

Open Splices

G G

Abrasion Marks

{£

{I {I

Broken Perfs

G G

Emul. Rubs

(

{1 \l

Nicked Perfs.

G G

Off Sprocket

a D

Hair Imbedded

G G

Blisters

a a

Hair In Neg

G G

Creases

a a

Static

G G

REMARKS

PICT. T

ACK

PICTURE i

SOUND

PICTURE

DEV.

ORIG. PRINT

DEV.

ORIG. PRINT

DEV

ORIG. PKINT

DEV.

ORIG.

Defective Printer

D D

Misframed

G G

Light Out

a a

Mislight

G G

Light Struck

D a

Mismatched Emul

G G

Static

a a

Short

G G

Optical Streaks

D a

Mis Synchronized

G G

Mistimed

a D

Rewind Scratches

G G

REMARKS

PICTURE

SOUND

PICTURE

SOUND

DEV.

ORIG. PRINT

DEV.

ORIG. PRINT

OEV

ORIG. PKINT

DEV^

ORIG.

Breaks

a n

Scratches

15" IB"

Creased Film

a n

Water Spots

G G

Emul. Peel

n a

Oil Spots

G G

Incorrect Dev.

a a

Streaks

G G

Imperfect Dry

a D

Stains

G G

Mechanical Trouble

a a

Stopped m Developer

G G

Power Failure

i n

a a

REMARKS

RY '

I Good

Picture Density !+*

Track Density Read

Quality {M

(*->

REPORT

Data

Inspected B)

Damaged By Projector

REMARKS:

Damaged Perforations

Sprocket Marked

Soiled In Handling

iY CUST. IT PLANT

REMARKS:

Incorrectly Ordered

Incomplete Instructions D

FIG. 3. Reverse of Fig. 2.

printing. The sound-track print, which was made as a fine-grain
high-quality track-print, is usually quite satisfactory as a printing
master for duplicating the sound to Kodachrome. As the very best
in quality with absolute minimum of noise is required in properly
produced instructional films, any defect (such as scratches, etc., how-

170 W. H. OFFENHAUSER, JR. \j. s. M. P. E.

ever slight) will result in the making of a new sound-track print for
duplicating purposes.

PRINTING

The Kodachrome Test Duplicate. — The Kodachrome original and
the sound-track positive are now sent to the Kodachrome printing
section. Kodachrome printing is kept apart from black-and-white
printing since only a weak green safelight may be used for Koda-
chrome. In this light, it is almost impossible to read quickly due to
the low level of illumination; for this reason, some form of auto-
matic pre-set printing-light-change arrangement, such as our pre-
perforated light-strip, is necessary for satisfactory scene changes
despite the slow printing speed of some twenty feet a minute.

The Picture Printer.— The improvement in lens resolution shown
by such projectors as the Eastman in comparison with the older
models of other manufacturers, as well as the increasing use of arc
projectors, makes high resolution a "must" on Kodachrome dupli-
cates.* The printers used for this operation are step-contact print-
ers having the movement claw within a frame or two of the aperture
where the duplicate is exposed. Light-changing is effected through
the customary notch in the original ; in this case, however, the notch
that effects the light-change automatically causes the pre-perforated
strip to set the light-intensity of the particular scene being printed.

At this point, something should be said about picture printer de-
sign and its effect upon the resolution of the copy. Any conven-
tional form of curved gate printer used for continuous picture print-
ing can provide good "contact" for only one definite and specific
shrinkage of the original with respect to the raw-stock used; this is
determined by the radius of curvature of the gate. It was to avoid
this handicap that sound-printers were forced to adopt the so-called
non-slip construction in order to be practical for sound-printing
purposes by accommodating somewhat wider shrinkage ranges.

Essentially, the same condition obtains in picture-printing, where
the non-conformity of the original to the raw-stock is accentuated by
the use of acetate-base materials. While there is little or no diffi-
culty with originals due to different shrinkages at the center and at
the edges when originals are stored loosely wound, a linear shrinkage
of 0.1 per cent or less in an original when new increases to a shrinkage

* See Appendix.

Aug., 1943] COMMERCIAL FILM LABORATORY 171

of the order of 0.5 per cent in a relatively short time (less than six
months). Since it is not unusual that a film-maker will expect to
make prints from training films that are a year or more old, curved
gate printer construction for Kodachrome picture printing is elimi-
nated; the only commercial solution in high-quality Kodachrome
production printing is slow-speed step-printing in a straight gate
using a claw type of film movement. It is only in this manner that
the contact printing ideal — that of printing in a still picture contact
frame — can be reasonably well approximated with present-day
equipment. All Kodachrome printed at Precision Film Laboratories
is printed on such equipment. It is costly, but it preserves the
quality of the costly original.

The Sound Printer. — Over a period of years, Precision Film Labora-
tories and its affiliated manufacturing company, J. A. Maurer, Inc.,
investigated the problem of 16-mm sound-track printing and came
to the conclusion that ordinary curved-gate contact printing of 16-mm
sound-film was hopelessly inadequate and that the usual non-slip
types were not applicable to 16-mm acetate-base films. If a piece
of 16-mm film is run between two rollers spaced even as little as four
inches apart, the film will appear to tilt first one way and then the
other; the effect seems aperiodic. It does not take much imagina-
tion to visualize what happens when such a film forms a loose loop
(as is formed by the upper loop in a non-slip printer); such linear
non-uniformity of one side of the film with respect to the other can
not possibly produce good contact, especially with the very low
value of kinetic energy provided by the film in motion. There would
appear to be no other practicable solution other than to put both
sound-negative and sound-positive under tension in their respective
printing loops and to print optically between them. It is an open
secret among designers that there are only a very few microscope
objectives on the market that can cover a sound-track with proper
field flatness and without appreciable illumination loss at the ends of
the area to be covered; the design problem included much optical
bench inspection of most of the microscope objectives commercially
marketed. It is interesting to note that the lens selected as most
suitable for the purpose was NOT made in Germany.

Optical sound- printing has several other advantages: it makes
possible quick interchangeability of whatever color-filters we choose
to use; the depth of focus of the optical system can be made large
with respect to the amount of in-and-out-of-focus film wobble ex-

172 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

perienced in printing; and printing either emulsion-to-emulsion or
base-to-emulsion can be accomplished at will. Last but not least, it
provides an excellent means of placing an image of high resolving
power upon Kodachrome duplicates; the only means commercially
available that begins to approach the resolving power of the image
that would be placed on Kodachrome by a recording optical system
itself.

At this point, it might reasonably be asked why picture is not
printed optically when optical printing of sound has shown such ad-
vantageous attributes. The answer is quite simple; suitable optics
are not being manufactured and marketed. It has been extremely
difficult to find suitable optics for the sound-track area of only one-
tenth of an inch; any attempt to cover three or four times that area
must be postponed until after the war; then, we hope, suitable optics
will be marketed.

After the Kodachrome test duplicate has been printed, it is packed
and shipped to the Eastman Kodak Company at Rochester for color
developing. Only one print is made; production prints are not
authorized until after the test print has beeen inspected and ap-
proved and the small corrections, if any, requested by the film-maker
are incorporated.

The Black-and-White Duplicate Negative. — While the Kodachrome
test duplicate is in transit, the original Kodachrome is turned over to
the chief timer for black-and-white timing A timing sheet for the
black-and-white duplicate negative printing is then prepared;
from this timing sheet another pre-perf orated timing strip is made up.
Within the last two years or so, we have found it practicable to use
the identical pre-perfprated timing strip for the black-and-white
duplicate negative that was used for Kodachrome printing. This
has been possible since we use the same kind of printer, only one
make and type of release-print fine-grain film — with accurate gamma
and density control; and only one make and type of fine-grain dup-
licate negative material* — also with accurate gamma and density
control. The film types used were selected on the basis of suita-
bility for the intended purpose; strange to relate, all three major
film manufacturers are represented as each seems to have a special-
ized technique in a specific material which places the particular
product "way out front."

* See Appendix for further data.

Aug., 1943] COMMERCIAL FILM LABORATORY 173

The Black-and-White Combined Test-Print. — If the duplicate nega-
tive is carefully made (and the Kodachrome original properly timed
for printing), the resultant black-and-white duplicate negative is
capable of producing highest-quality release-prints without any
picture light-change whatever in the release-printing operation.
Here again, the same kind of printers are used as for Kodachrome
printing; step-contact printers with straight gates for picture and
optical one-to-one printers for sound. All films that have been
shown to the Society in the last two years by Precision Film Labora-
tories, by J. A. Maurer, Inc., or by any of the customers of Precision
Film Laboratories have been printed in the manner described.
Needless to say, considerable effort and planning were necessary to
put the system into operation commercially, and a number of prac-
tical details had to be worked out to integrate the procedure. As a
production matter, this kind of procedure seems to be today's solu-
tion of the problem of high-quality mass-production 16-mm black-
and-white printing.

The Black-and-White Fine-Grain Release Print.- — As soon as the
black-and-white test-print is inspected by the film-maker, black-and-
white protection sound-track prints are made; new duplicate nega-
tives are made also (for parallel release printing and for protection)
and the black-and-white release-prints are "ready to roll." The
original sound-negative is ordinarily used in all release printing;
it is not unusual for as many as a thousand or more prints to be made
from the sound-negative original. With machinery properly de-
signed, maintained, and operated, sound-negative deterioration
should be almost minute. In laboratories that do not specialize in
16-mm film, here again the "mortality" rate runs quite high.

The Color Duplicate. — In the meantime, the color test duplicate
has been returned from color development by Eastman Kodak
Company and is ready for inspection. It is screened by the timer
together with the film-maker ; the timer then indicates on his timing
sheet the corrections desired. A new pre-perf orated timing strip
is made in accordance with the corrected timing for the release color
duplicates. It is not unusual to make as many as two hundred
Kodachrome duplicates from the same original; the uniformity from
one duplicate to another is just about as good as the color develop-
ment uniformity in Kodak-processing.

Multiple Color Duplicates. — Experience indicates that if printing
machinery is well designed and well maintained, and if the film is

174 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

carefully handled by competent and well trained personnel, few
printing "accidents" will occur and the two-hundredth duplicate of
a Kodachrome original should be, if anything, even better than the
first or second, due to the experience gained. Good machinery
properly maintained and properly operated causes very little wear
on an original film.

Multiple Black-and-White Prints. — With regard to black-and-
white fine-grain prints, the same may be said. As the number of
black-and-ivhite prints required of a subject may run over a thousand,
some form of parallel printing operation is necessary for volume out-
put. The procedure outlined needs but one further step: the pro-
vision of a suitable number of sound-track negatives for printing
when a large number of prints is to be made in a short time. These
are best obtained by re-recording; photographic methods are still
decidedly inferior and should not be used if best and most uniform
quality from print to print is required. At present commercial rates,
sound-tracks can be re-recorded by competent and properly equipped
16-mm studios for as little as $35 to $50 per 400-ft reel; where a
number of identical copies is to be turned out, the price may be even
lower. As it is not unusual for a re-recorded negative to be used for
500 or more prints of the same subject, the addition of only some 7
cents per print to the printing cost due to re-recording is one of the
cheapest kinds of good sound-insurance that money can buy.

Kodachrome and Black-and-White Protection Prints. — When a
large number of prints is to be made from an original Kodachrome,
one of the first matters for consideration is that of "protection prints."
In our recent mad rush into 16-mm prints (from whatever originals),
we have paid the usual lip service to protection prints but have not
been especially concerned whether they fulfilled their intended func-
tion or not. If it is remembered that a protection print has as its
function the making of further prints in the event that the printing
master is damaged, not only would considerably more care and
planning be used in their making but also they would command a
much higher price. To provide properly for protection prints, we
need not only protection for the picture but also protection for the
sound. In the case of the picture, the best color protection print is a
selected combined duplicate from the production run. No two
prints are absolutely identical in quality; if every color duplicate is
completely projection-inspected (as is absolutely necessary for
accurate quality control of the product) it does not take an intelli-

Aug., 1943] COMMERCIAL FILM LABORATORY 175

gent inspector very long to select one of the best color duplicates of
the production run. As protection for the black-and-white prints, it
is advisable to make additional dupe negatives at the time the extra
dupe negatives are made for the black-and-white print run. In
general, the number of additional dupe negatives made as protection
should be a percentage of the total number of prints expected after
the initial print run is completed.

For protection of the sound, the original sound-track print used
for re-recording the multiple black-and-white re-recorded negatives
is the best protection possible. If this is in any way scratched or
otherwise damaged, a new print (sound-track only) should be made.
It is always possible at a later date to re-record from that positive
should new printing negatives be needed.

Specific Recommendations for Protection Prints. — In the case of a
production where a large print run is planned for both the Koda-
chrome and for the black-and-white, let us say 200 Kodachrome dup-
licates and 1000 black-and-white prints, the following protection
prints would be desirable :

(a) Two Kodachrome combined duplicates (to be used as printing masters in
the event of loss or damage to the original picture).

(6) Two black-and-white sound-track positive prints of the original sound-
negative. (One of these would be printed emulsion-to-emulsion and the other
printed through the base.)

All of these, with the possible exception of (a), should be made at
the start of the release printing run.

Reasons for These Recommendations. — (a) The combined dup-
licates to be made can be considered reserve master duplicates; one
or the other would be used for printing further release runs in the
event of loss or damage of the original. It is to be noted, however,
that since these films are contact-printed, second-run duplicates so
made would have the standard emulsion position while the original-
run duplicates will have the non-standard emulsion position.

While there is appreciable photographic loss in release duplicates
made in this manner from a master protection copy, it is surprising
how satisfactory such copies may be if the original was excellent and
the copying work accurately controlled. It is not unusual for such
secondary-run duplicates to provide better screen quality than the
average first-run duplicates made in laboratories that do not special-
ize in 16-mm work.

176 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

(b) One sound-track positive of the two recommended is intended
as a protection sound-positive to be used in printing additional first-
run Kodachrome sound-duplicates from the original Kodachrome.
In addition, this positive may be used also for re-recording addi-
tional sound-negatives for further black-and-white release runs.

The second sound-track positive is intended as a protection sound-
positive to be used in printing second-run Kodachrome sound-
duplicates from the master protection Kodachrome copy.

(c) The black-and-white duplicate negatives recommended are
to be used for later black-and-white release runs; new duplicate
negatives as made for release-printing purposes are preferably placed
in storage and the older ones removed from storage and used. In
this manner, the optimal state of preservation is maintained.

Storage of Protection Prints.— Unfortunately, one major factor
that is responsible for the poor quality of the 16-mm prints at present
being purchased in very large quantity by the Government for train-
ing and related purposes, is the absence of an intelligent protection-
print policy. A suitable policy encompasses not only a definite plan
as to how and when and with what quality protection prints are to be
made, but also where such prints are to be stored. While much
specifying of protection prints is done, the actual problem of where
and how such prints are to be stored has been unceremoniously
dropped into the laps of the release-print laboratories. This has been
a carry-over from peace-time practices when laboratories used film
storage as a factor in the competition for business.

The laboratory is NOT the proper place to store these protection
prints; they should be stored by the film-maker himself, preferably
on his own premises, where they are NOT out of sight and out of
mind.

If the recommended protection films are stored approximately
one week in the ordinary way and, at the end of the interval, placed
in individual properly marked film cans and mounted on cores some-
what loosely wound, they will have dried sufficiently to be ready for
storage. The can should be thoroughly dried (carbona will both
clean and dry) and the film put into it. The can is next sealed with
Kodatape or other adhesive of equivalent sealing ability.

If these cans are then stored in an electrical refrigerator whose
temperature is set for about 50 degrees, all indications point to suit-
able storage for both the Kodachrome (image deterioration is essen-
tially inhibited) and for the black-and-white films. In both cases,

Aug., 1943] COMMERCIAL FILM LABORATORY 177

shrinkage is also essentially inhibited; although the film may shrink
somewhat when later taken out of the can, the shrinkage rate will be
slow enough to permit the use of the film at least for a period long
enough to permit making the desired prints. The storage char-
acteristics of 16-mm films have improved considerably in the last
few years, and still further improvement will doubtless come after
the war is over.

Technical Requirements of Protection and Other Good Prints. — In
the JOURNAL there are numerous papers on methods of measuring
and reducing residual hypo. There have also been occasional refer-
ences to the use of film "preservatives." Unfortunately proper
washing and drying of films is the exception rather than the rule;
it must be remembered that a protection print provides no protec-
tion whatever unless it is properly washed and dried.

"Green" Film.— On April 14, 1939, the Research Council of the
Academy of Motion Picture Arts & Sciences issued a Technical
Bulletin, "Report on Film Preservative Tests," which describes
"green" film:

"Treatment given to release-print film after it has been printed, developed,
and dried is commonly called 'film preserving,' and the processes by which this
treatment is given are known as 'film preservative' processes.

"The gelatin of freshly developed film carries a high percentage of moisture in
its pores and as long as this condition prevails is known as a 'green' emulsion.
A so-called 'green' emulsion is quite soft and the slightest abrasion will cause a
scratch. These scratches widen out as the gelatin dries, and cause the 'rainy'
effects seen on the screen in the theater.

"As film with 'green' or soft emulsion passes through a projector, it leaves
small deposits of emulsion on the tension shoes at either the aperture plate or
the sound-gate, unless the tension shoes are kept thoroughly lubricated. Such
deposits build up resistance to free passage of the film over them, and scratch
the film during projection.

"When the moisture in a 'green' emulsion is withdrawn too quickly, the gelatin
shrinks and the film warps or buckles. If too great an amount of moisture is
withdrawn from the gelatin, the film becomes brittle, loses its pliability, and is
easily torn while being projected."

The subject of green film is ordinarily considered "delicate;" it is
too often explained away rather than investigated. It is not un-
reasonable to believe that a major source of difficulty with such films
as those untreated films described is just plain improper drying in
the drybox of the developing machine. If one attempts to project
an ordinary mass-produced low-price 16-mm "green" print made

178 W. H. OFFENHAUSER, JR. [jr. S. M. P. E.

under the average Government contract, it will not even go through a
projector without some form of film "preservative" or lubricant.

There are two ways to look at the problem of green 16-mm prints:
one is to accept improper washing and drying as a fact, and hope that
a film "preservative" will accomplish the miracle; the other is to
wash and dry the film properly. This job is not impossible; in our
laboratory we have been 100-per cent projection-inspecting film in a
matter of minutes after it is removed from the drybox take-up of the
developing machine, and no "film preservative" whatever is used to
"ease" the film through the projector. The reason is simple: the
film when so washed and dried is not green. This procedure is not
an innovation; the drybox is merely several times as long as the
developing tank and, in addition, excess hardener is used in the hypo.
In the average case, the drybox of the developing machine is only
about one-fourth of its proper length and proper cubic-foot content
as determined by the speed at which it is currently operated. It
would seem the better part of wisdom to reduce our breakneck
speed in order to tighten up on our inspection and improve our
quality. It has been too often considered competitively advanta-
geous to run machines at 400 feet per minute (in order to cut prices)
when a fraction of the output in the form of really good quality films
would far better serve the ultimate purpose.

A good rule to follow is that if a projector will not project an un-
treated new film satisfactorily, there is something wrong with the
film (most likely), something wrong with the projector (less likely),
or both. If Government specifications will require that films be pro-
jection-inspected and approved immediately after removal from the
developing machine and prior to any "vaporating" or "preserving,"
there will be a remarkable increase in the life of prints purchased for
circulation as well as a great reduction in the waste of film, chemicals,
and labor now resulting from the scrapping of films that die long
before their normal life span should be over.

The importance of proper washing and drying is only now begin-
ning to be appreciated. If we project a carefully processed fine-
grain film on a 12 or 15-ft screen with an arc projector such as a Bell
& Howell equipped with sound and picture optics of Eastman Kodak
quality, the film must lie perfectly flat in the gate or in an accurately
predetermined position if the screen image is to be as* satisfying as in
35-mm theatrical projection. This is no chore when films are prop-
erly washed and dried; unfortunately, proper washing and drying

Aug., 1943] COMMERCIAL FILM LABORATORY 179

are not as widely done as we would all like. This is another point,
incidentally, where it is possible for a laboratory to "cut corners" in
order to cut price.

High-quality 16-mm prints can now be obtained in fair volume
but, as always, specialization is required properly to accomplish the
intended result. Ordinary positive film does not have sufficient
resolution to provide the performance specified for 16-mm films in
16-mm projectors; fine-grain films properly processed do have
sufficient resolution, not only for the picture but also for the sound.
For the sound, only optical one-to-one printing can provide suitable
resolution.

When properly processed fine-grain films are used in properly
designed, properly maintained, and properly operated projectors,
the result is of theatrical quality and suitable for audiences (in
proper auditoriums with proper screens and proper acoustics) up to
about 500 or 1000. If the result in a particular case is not satis-
factory but the machinery, auditorium, etc., are known to be up to
par, the film then becomes suspect.

APPENDIX

Notes on Fine-Grain Film and Its Processing in a Commercial 16-MM Laboratory
General. — While the contracts let by the Government for present-day bulk
printing of war films are quite long and complicated and usually have a long and
intricate questionnaire as an integral part, a study of the release-prints made
under such contracts seems to show on the whole a disregard for technical quality.
In the past emphasis has been placed upon quantity and low price in an effort to
get out the work; one of the possible causes for this one-sidedness may well have
been the paucity of reliable published data concerning the resolving power of
film materials developed in commercial developers.

It has long been recognized that the film to be used for a particular purpose
should be capable of clearly rendering the very fine lines of the image to be repro-
duced— whether the image be of picture, of sound, or, for that matter, of any
other form of photographic intelligence. Generally speaking, the greater the
resolving power (minuteness of detail — measured in lines per millimeter) of the
films and machinery used in the making and showing of a sound-film, the better
the quality of the performance seen and heard by the audience. Although the
industry recognized the importance of resolving power, manufacturers were
reluctant to publish resolving power data or to attempt to discuss the subject in
other than qualitative terms. "Fine grain" was considered laudable; but there
was no way for a film user to determine how fine "fine grain" had to be.

A convenient quality datum for 16-mm projection is the quality obtained in
the conventional 35-mm entertainment motion picture theater.1 Projection
equipment, both picture and sound, have been standardized and even the theaters
themselves have been considered for standardization. Sound has been standard-

180 W. H. OFFENHAUSER, JR. [j. s. M. p. E.

ized; the projection equipment characteristics published by the Academy of
Motion Picture Arts & Sciences have been an effective and reliable guide for
several years. With this convenient reference, it is only necessary to extra-
polate from the experience of the larger-size film into that of the smaller.
If we wish to match the quality found in the entertainment motion picture
theater when we project 16-mm prints, the latter prints must be capable of
rendering all the detail of the larger film. This is accomplished, so far as the
print raw-film is concerned, when the detail-rendering ability of the 16-mm
positive is equal to that of its 35-mm counterpart. The resolving power of the
16-mm positive film must, therefore, be numerically equal to that of the 35-mm
positive film multiplied by the ratio of the film areas. Since the area to accom-
modate the image on the 35-mm film is 21/2 times that available to accommodate
the image on 16-mm film, the resolving power of the 16-mm film in lines per milli-
meter must be 2l/2 times that of the 35-mm film for equivalent results.

The industry has been most fortunate recently in obtaining authoritative pub-
lished data on the resolving power and other characteristics of Eastman film ma-
terials.8 The data presented now make it possible to judge quite reliably in a
quantitative way the most suitable Eastman material for a particular application.
The remainder of this Appendix will be devoted to the practical application of
these data and to the suitability of the various materials for their intended pur-
poses. Throughout this discussion it should be borne in mind that the difference
between 35-mm film and 16-mm film of a given emulsion type is merely the width
to which the material is slit; Eastman 1301 ordinary positive 35-mm film, for
example, has the same emulsion as Eastman 5301 ordinary positive 16-mm film.

Resolving Power. — Since the resolving power of Eastman 1301 is 55 lines per
mm, it is apparent that a 16-mm positive material must have a resolving power of
55 X 2x/2 or 1371/2 lines per mm or more, for equal or better performance. Ac-
cording to this criterion, Eastman 5302 fine-grain positive, while it is a fine-grain
material, is not fine enough for the purpose; its resolving power is only 90 lines
per mm. It is obvious, therefore, that for detail -rendering equal to that of the
35-mm entertainment motion picture theater, Eastman 5302 fine-grain will not
qualify; however Eastman 5365 fine-grain positive has a resolving power of 150
lines per mm, a detail-rendering ability considerably beyond the minimum re-
quired. For detail-rendering ability equal to that of the 35-mm entertainment
motion picture theater, Eastman 5365 is satisfactory in 16-mm.

From these figures, it should be obvious that the use of 16-mm ordinary posi-
tive materials such as Eastman 5301, Dupont 600, Agfa 220, and others of similar
resolving power, can not produce results on a 16-mm screen that are at all com-
parable with the results found on the usual 35-mm entertainment screen. The
resolving powers of all are of the same low order. However, that while Eastman
5302 does not qualify, it is to be definitely preferred to material of lower resolv-
ing power.

Dupont has not published data on a comparable basis. It is known, however,
that Dupont 605 fine-grain positive has resolving power of similar order to that
of Eastman 5302. It is to be hoped that Dupont, Agfa, and the American
Gevaert Company will soon publish similar data on a comparable basis so that
materials may be intelligently selected for their intended applications.

The Practical Aspects of Application. — Theoretically, to preserve all the detail
of an original film, it is necessary that the resolving power of every intermediate

Aug., 1943] COMMERCIAL FILM LABORATORY 181

material and machine and of the release-print material be as high as possible with
respect to the resolving power of the original. This goal, while sought after, is
only approached; we measure our achievement by the size of the gap between
our practical result and our ideal.

Cost vs. Speed. — It is true that fine-grain materials are inherently slow photo-
graphically; it was for this reason that Dupont, in referring to Dupont 605 film
in their brochure "Sixteen Millimeter Dupont Motion Picture Film," stated,
"To date it has been impossible to get sufficient light for reduction printers to
use this slow film for prints from 35-mm negatives." If the same developer and
the same printing machine operating at the same film speed is used for 605 as for
ordinary positive, the statement is true especially for conventional designs of
machinery. This film can be used, however, if the proper compensating steps
are taken in the proper amount: (1) increasing the energy of the developer;
(2} increasing the intensity of the light-source or improving the efficiency of the
optics of the exposing system ; (3} reducing the linear speed of the film through
the printer to increase the exposure time by the proper amount. Just how the
compensating steps are to be apportioned is a matter of designer's choice; re-
gardless of the balance finally chosen, the cost of fine-grain printing and develop-
ing is going to be higher than the cost for ordinary positive.

Gamma. — On occasion we hear the remark "I tried fine-grain film and it didn't
work." Further investigation usually shows some lack of understanding of the
fundamentals of film technique. One common failing is the lack of appreciation
of the importance of overall or print-through gamma.

If we desire good gradation in the picture image, it is important that we plan
quantitatively how to obtain it — we must avoid the common fault of "piling up"
contrast in each successive-processing step through which the film passes. Fine-
grain positive has higher contrast than ordinary positive and a compensating
reduction in gamma must be made at some earlier stage if "washing out" is to be
avoided. It is just as important in 1943 to avoid "piling up" contrast by the in-
discriminate use of high gammas as it was in 1929 when we first began to appre-
ciate the real significance of the term. Most of the 16-mm prints made under
the Government bulk printing contracts exhibit an overall or print-through
gamma far too high for even ordinary positive film; the use of the same tech-
niques in connection with fine-grain materials can not but result in failure. Much
could be accomplished to correct this condition if Government contracts would
stress overall gammas; a very simple qualifying test for any laboratory desiring a
Government contract would be to make a spliced test-roll of 50 feet containing
the original and three sections of a reproduction from the same reversal original
in sequence — the first, the positive print from the first dupe negative; the second,
the print from the dupe negative of the first positive print; and the third the
print from the dupe negative of the second positive print.

Contrast Control. — It has been said that one of the most advantageous char-
acteristics of negative-positive processing is the control of overall gamma. This
excellent method is of no value, however, if it is not used — and most of the 16-mm
prints show little evidence of its use. If fine-grain release-print materials are
inherently more contrasty than ordinary positive, it is obvious that a fine-grain
print made from a particular original will be more contrasty than its ordinary
positive counterpart, whether the original be 35-mm or 16-mm. The original
negative must be made "softer," or an intermediate master positive and inter-

182 W. H. OFFENHAUSER, JR.

mediate duplicate negative of gamma product less than unity must be made, to
correct for the expected contrast increase. Once again the method chosen is a
matter of designer's choice, and once again, regardless of the method chosen, it
will cost a little more to do the job properly with fine-grain film.

Contrast control in direct 16-mm black-and-white is obtained by the original
reversal (Kodachrome) -duplicate negative-fine-grain positive processing method.
The starting point is a direct positive; the number of steps used is one less than
ordinarily needed for optical reduction from 35-mm. In the direct 16-mm case,
it should be obvious that print contrast is controlled almost entirely in the making
of the intermediate duplicate negative. The most suitable Eastman material is
Eastman 5203 duplicating negative; it has a resolving power of 110 lines per mm,
which, while a little shy of the goal, is sufficiently close for practical purposes.

Kodachrome. — Kodachrome, it should be noted, has been unjustly accused of
quality inherently inferior to that of black-and-white prints. The data pre-
sented show the opposite to be true in the case of ordinary positive; Kodachrome
has a resolving power of 75 lines per mm; Eastman 5301 ordinary positive has a
resolving power of only 55 lines per mm. If sound or picture reproduction in
Kodachrome duplicates is poorer than in black-and-white prints on ordinary
positive, the fault should be sought elsewhere than in the material.

The following table is abstracted from the Eastman publication2 referred to;
the gammas specified are considered representative of good practice by Eastman
Kodak Company but are not necessarily used by Precision Film Laboratories.

Resolving
Type Number Power Lines per Mm Gamma Developer

1301 55 2.0-2.20 D-16

5302 90 2.40-2.60 D-16

5365 150 1.20-1.60 *SD-21

5203 110 0.60-0.70 *SD-21

REFERENCES

1 MAURER, J. A.: "Commercial Motion Picture Production with 16-Mm
Equipment," /. Soc. Mot. Pict. Eng., XXXV (Nov., 1940) p. 437.

2 MAURER, J. A.: "The Present Technical Status of 16-Mm Sound-Film,"
J. Soc. Mot. Pict. Eng., XXXIH (Sept., 1939) p. 315.

3 OFFENHAUSER, W. H., JR., AND HARGROVE, F. H.: "Some Industrial Appli-
cations of Current 16-Mm Sound Motion Picture Equipment," J. Soc. Mot.
Pict. Eng., XXXI (Feb., 1940).

4 SNYDER, WILBERT F.: "Acoustic Performance of 16-Mm Sound Motion
Picture Projectors," Bureau of Standards Circular C439 (July, 1942).

5 STEPHENS, ROBERT E. : "Optical and Mechanical Characteristics of 16-Mm
Motion Picture Projectors," Bureau of Standards Circular C437 (June, 1942).

6 Report of the Committee on Non-Theatrical Equipment: "Recommended
Procedure and Equipment Specifications for Educational 16-Mm Projection,"
/. Soc. Mot. Pict. Eng., XXXVH (July, 1941) p. 22.

7 OFFENHAUSER, W. H., JR.: "A Review of the Question of 16-Mm Emulsion
Position," /. Soc. Mot. Pict. Eng., XXXIX (Aug., 1942), p. 140.

8 "Eastman Motion Picture Films for Professional Use," Eastman Kodak
Company (Rochester, N. Y.), 1942.

THE PROJECTION OF MOTION PICTURES

HERBERT A. STARKE**

Summary. — The final phase of motion picture production is in the theater, and
the success of this phase depends upon the technique of projection and the condition
of the projection equipment.

The paper discusses in considerable detail the importance of proper maintenance,
the types of light- sources, and other factors of importance to good projection.

The final phase of a motion picture production is in the theater.
All the preparation and expenditure of money involved in its creation
have now been reduced to so much film footage. It is now in the
hands of the projectionist, with whom lies the responsibility of trans-
ferring the material to the screen, through the medium of projectors
and a source of light. Motion pictures are an illusion, and are in-
tended to convey realism to the screen.

Upon the arrival of the release print, the normal procedure in first-
run theaters is a careful inspection and measurement of the entire
footage. For several years, the exchanges have been doubling up the
reels of features for shipment. This duty is performed for the most
part by girls in the exchange. In other words, the composite film is
delivered to them on spools from the laboratory ; they in turn mount the
A and B sections on 2000-ft reels. Our experience has been that in
many cases, this very important procedure is not properly handled.
Most of the splicing is done with small mechanical splicers, which is
allowed to become worn and out of alignment, with the result that
inaccurate splices are made. Many of the girls engaged in this work
do not realize the importance of properly blooping out splices. The
splicing lacquer is allowed to become thick and slow-drying; and as

* Presented at the 1942 Spring Meeting at Hollywood, Calif.
** RKO Service Corp., Hollywood, Calif.

183

184 H. A. STARKE [j. s. M. P. E.

re-winding proceeds, deposits from the wet application are smeared
on the track over several wraps. This necessitates cleaning with a
lacquer remover, and invariably the splices are removed. Under no
circumstances are the shipping reels used; they are, for the most part,
badly bent and unfit for use. Most of the best theaters are equipped
with cast aluminum reels, upon which the film material is mounted
for the duration of the engagement.

It was the practice of first-run theaters in the early days of sound to
conduct complete rehearsals before the opening of new pictures. The
chief projectionist checked the volume from the auditorium, cues
were made, and a general knowledge was acquired of the complete
show. Today, unfortunately, this practice is not usually followed,
with the result that the new shows are opened without the crew's
having any accurate knowledge of the volume required. They de-
pend solely upon booth monitoring.

Projection room routine will vary from theater to theater. Never-
theless, certain duties must be performed daily. Of great importance
are the inspection and cleaning of the following units :

(1} Projector mechanisms.

(2} Upper and lower magazine valve assemblies.

(»?) Optical systems.

(4) Lamp houses, contacts, and all component parts.

(5) Take-ups and belts. Proper oiling with manufacturer's specified lubricant.
Many projectors have been ruined by inferior oils.

(6) Inspection of sound system.

(7) Inspection of generators or rectifiers. Motor switches must be replaced at
regular intervals. A failure here may cause interruption of the performance.

It is important that the light from each projector be checked on the
screen for intensity and color, and at the same time, image alignment
should be checked. Every effort should be made to ascertain that the
shutters are perfectly timed ; slight bleeding that may not be observed
from the projection room will cause loss of definition.

There appears to be considerable lack of showmanship today, and
the absence of lighting effects is noticeable. The general procedure is
to work out a schedule, the starting time is determined, and the show
is on. The practice of giving away cash and other prizes, in many of
our de luxe theaters has not enhanced the production but rather has
cheapened it.

Aug., 1943] PROJECTION OF MOTION PICTURES 185

The success of the presentation depends largely upon technical con-
ditions often beyond the control of the projectionist. The equip-
ment in many of our theaters today is inadequate, particularly with
respect to the available light, Theater managers seem to be reluctant
to seek proper advice when purchasing lamp equipment, and false
economy often results in inadequate projection. *

Light sources may be divided into three categories: (1) the largest
theaters require condenser-type high-intensity arcs ; (2) the interme-
diate theaters the Suprex type; (5) and the small theaters the 1-kw
a-c or d-c types. Due to its yellow color and low intrinsic brilliancy,
the low-intensity arc is being rapidly replaced by an intermediate
type of non-rotating high-intensity arc having a color value approxi-
mating the white light of the rotating and non-rotating high-intensity
arcs. The reflected screen light depends upon the character of the
source, the optical system, and the reflectivity of the screen ; and last
but not least, upon the efficiency of operation. To the projectionist
falls the task of coordinating these elements into a single, smoothly
operating whole.

Dense prints are quite common today, and it is also becoming the
practice to increase the auditorium illumination. Smoking is per-
mitted in many theaters, tending to decrease reflectivity of the screen.
The* projectionist in the large theaters using the Suprex equipment in-
stead of the high-intensity condenser arcs will often increase the arc
wattage beyond the rated capacity of the carbon trim in an attempt
to increase the brightness of the picture. He then encounters a dis-
proportionate increase in carbon-burning rate, often beyond the feed
rate of the arc control mechanism. Operation then becomes critical
and efforts at manual control prevent the arc from establishing itself
on a stable basis.

There has been a tendency, particularly on the West Coast, to in-
crease the picture size without adding to the illuminations, whereupon
a reduction in brightness and contrast results. Graininess is also
noticeable, and all these factors lessen the value of the front rows of
seats.

Operating difficulties may be encountered with the rotating high-
intensity lamp, due to pitted or burned contact brushes, loose and
dirty lead connections, excessive voltage at the arc. The carbon
manufacturers' specifications should be rigidly followed. The lamp
house should be ventilated, if possibe, with a separate exhaust fan,
and dampers put into the stack in such a manner as to control the

186 H. A. STARKE [j. s. M. P. E.

travel of air without impeding the passage of waste materials of arc
combustion.

The Suprex and the 1-kw types of non -rotating high-intensity
lamps are operated at small arc voltage and current. Hence, they
are sensitive to drafts. Modern lamp houses are designed to have
sufficient ventilation under ordinary conditions, but close control of
the amount of air passing through the lamp houses into the stack is
essential for trouble-free operation. Abnormal draft is caused by
excessive ventilation of the projection room, back-draft from certain
types of rear shutters having cooling fins, and down drafts from chim-
neys lacking forced-draft ventilation. Excessive draft, unless very
strong, does not usually cause flickering, but it does cause a move-
ment of the arc flame, which becomes noticeable on the screen.

The non-rotating high-intensity arc, when properly burned, is
almost rectangular in form, with the point of the tail flame directly
above and not far behind the positive crater. If the tail flame wavers
and is driven toward the front of the lamp house in an intermittent
manner, excessive draft is usually indicated.

If it is not possible to control the draft with the stack damper, it may
be necessary to restrict the ventilation entering the lamp house; or,
if the trouble is caused by fins on the rear shutters, the fins may be
removed. However, this procedure is not recommended, as the fins
were installed to dissipate heat from the film and the film-trap assem-
bly. It is suggested that the arc be protected by means of a heat-
proof glass shield placed directly behind the rear shutters. It should
be remembered, however, that adequate ventilation is necessary to
protect the lamp house, and drafts should be restricted only to the
point at which the arc will burn satisfactorily.

In order to maintain a rectangular arc shape, as described, it is
necessary that the carbons be properly positioned, by raising and
lowering the negative carbon until the gases are seen to escape from
the top of the positive crater. For higher currents, the negative car-
bon tip should be slightly below the centerline of the positive, and in
order to let the gases escape from the top of the crater, it may be
necessary to allow the top of the positive crater to burn back as much
as 0.32 inch.

Anything that disturbs the normal position or function of the arc,
such as some types of carbon savers, or by burning the carbons too
short, may result in screen discoloration, light reduction, or change
in light distribution.

Aug., 1943] PROJECTION OF MOTION PICTURES 187

The optical system of the non-rotating high-intensity lamp is de-
signed by the manufacturer to deliver the maximum amount of light,
and the arc should be operated in a given position with respect to the
mirror. Moving the positive crater toward the mirror 0.10 inch from
its proper distance will result in a decrease in screen illumination of
approximately 40 per cent when using a 7-mm positive carbon.

In order to avoid noticeable screen color difference, the arc should
be struck three or four minutes before the change-over period and
the position of the image of the positive crater should be adjusted
before, not after, the change-over. In many theaters where false
economy prevails, projectionists are instructed never to strike the
arc on the incoming projector until the last minute. With this pro-
cedure, screen results are bound to suffer.

When illumination trouble occurs it is necessary to locate it with a
minimum of delay. Unfortunately, it is often difficult to determine
immediately whether or not the carbons are at fault, and some pro-
jectionists keep a few trims in a dry place to be used as a check. Later
if trouble occurs, carbons being currently used are checked against
these reserves. If the trouble persists, one may look elsewhere for it,
such as in the current supply or in the condition of the draft. Rarely
are the carbons found to be at fault.

With the releasing of productions on fine-grain stock, hopes were
entertained that some of the lighting problems would be lessened.
Experience in this respect has been, to say the least, very disappoint-
ing. The greater brilliance and contrast are readily apparent, but
the stock used so far has a tendency to buckle. The phenomenon is
very curious: it comes and it goes. A print may be used for a few
days without trouble; then, for no apparent reason, the picture on
the screen begins to weave in and out of focus. In other words, the
photographic image will be out of focus.

The modern projector is designed to be adaptable to all types of
theaters. There are, however, many mechanisms now in use, par-
ticularly in circuit houses, that should have been discarded years ago.
Worn film-tracks and hooked sprockets are found in many of them,
which are the causes of film damage in alarming proportions. Many
projectionists have adopted the practice of speeding up their electric
rewinds beyond the limits. set by the manufacturers. This causes
many fine scratches on the surface of the film, commonly called
"rain," and should not be tolerated.

It is difficult to understand why so many owners and managers will

188 H. A. STARKE [j. s. M. P. E.

not hesitate to make large expenditures on new marquees, carpets,
chairs, and on the general beautifying of the auditorium, all of which
can not be fully appreciated in the dark, but neglect to maintain
properly the most vital part of their theater — the projection equip-
ment. The screen is allowed to become dirty and discolored. There
are many methods of so-called resurfacing; few have proved satis-
factory. The best procedure is to try to keep the surface and perfora-
tions free from dust and dirt. When discoloration does take place,
the screen should be replaced. The difference in cost between an or-
dinary resurfacing job and a new screen is not comparatively great.

Many of the older theaters were constructed during the days of
vaudeville and stage presentations. The picture was of secondary
importance; consequently little if any attention was given to the
planning of the projection room, which, with very few exceptions,
were small and poorly ventilated. They were, in most cases, con-
structed high above the balcony to avoid the loss of seating space.
The cost of redesigning them to present-day standards would be pro-
hibitive.

Picture distortion and keystoneing are present. Squaring the pic-
ture image by aperture-plate correction improves the general appear-
ance, but the situation is a serious handicap to good projection. It is
unfortunate that such conditions prevail in many of our first-run
houses.

Notwithstanding these and many other factors, projection has for
the most part improved steadily.

In 1936 the Research Council of the Academy of Motion Picture
Arts & Sciences recommended the standard leader and the placing of
dots in the upper right-hand corner of the composition for change-over
cues. This practice was adopted by all the large producing com-
panies, and provides a successful means of properly changing from one
reel to another. Yet there are still some projectionists who deliber-
ately deface the ends of reels with cues of their own design, such as
punch marks or crosses scratched into the emulsion, all tending to
impair the print and detract the audience's attention from the sub-
ject being reproduced upon the screen. True, the laboratories do not
provide standard cues on many short subjects, such as newsreels and
trailers, and it is necessary that some sort of cue be provided. A small
inexpensive cue-marker consisting of a template and a hardened
steel scriber is recommended, for .scribing a small circle at the upper

Aug., 1943] PROJECTION OF MOTION PICTURES 189

right-hand corner of the film image, at exactly the spot where the
standard dots would appear.

Conservation is all-important today, and replacement parts will
not be obtainable. It is therefore urgent that equipment should be
properly checked and adjusted. There is no reason why an intermit-
tent sprocket should not last at least three years, provided it is of the
manufacturer's specifications and the tension pads and shoes are
properly adjusted. Excessive tension not only shortens the life of the
sprockets, but also causes undue wear throughout the entire projector
mechanism. One method of increasing the life of tension pads and
shoes is to have them ground perfectly true and then chromium-
plated. This also eliminates the tendency of new (or "green") film to
stick while being projected.

Space does not permit a complete discussion of the many important
units that tend to make up the modern projection room. Projection
may be termed the bottle-neck of the industry, and there is much that
can be done in the projection room to assist in placing upon the screen
high-quality pictures reflecting the great amount of labor, art, and
expense that went into the making of the production in the studio.

APPLICATION AND DISTRIBUTION OF 16-MM
EDUCATIONAL MOTION PICTURES*

F. W. BRIGHT*5

Summary. — The proper distribution and application of 16-mm motion pictures
require painstaking planning and continued follow-through. . With this in mind, the
methods of distribution are considered with respect to the three major fields of business
employing 16-mm pictures, viz., (1) public education; (2) sales training; (3) per-
sonalizing messages from home offices to field personnel.

The proper application and distribution of 16-mm motion pictures
is not a hit-or-miss proposition. Rather it is an exact science de-
pending almost entirely upon painstaking planning and continued
follow-through.

Too often producers and users of 16-mm pictures neglect to give
this phase of the program the necessary attention. Too much
emphasis is placed upon achieving mechanical perfection in the
picture, and too little upon the ultimate effect upon the audiences,
with the result that the picture fails in the job for which it was in-
tended.

Since 1934, when we distributed our first 16-mm public release,
the results of this medium of visual and oral education have been
excellent, because the application and distribution plans have been
carefully considered well in advance of the release dates.

At present we are enthusiastically producing and using 16-mm
films in three major fields — (1) public education, (2) sales training,
and (3) personalizing messages from Home Office officials to our
field personnel.

Public Education. — Before releasing any picture for the public,

* Presented at the 1942 Fall Meeting at New York, N. Y. ; received October
25, 1942.

** Supervisor, Motion Picture Bureau, The Aetna Casualty and Surety Co.,
Hartford, Conn.
190

EDUCATIONAL MOTION PICTURES 191

the distribution is carefully planned, step by step. This procedure
is demonstrated by one of our educational health releases. The
first step in planned distribution is to arrange formal previews by
recognized authorities on the subject. Invited to these previews
are representatives of the local or state medical societies, key members
of hospital staffs, dietitians, representatives of stand and local
health departments, and others who have a real interest in the sub-
ject. After seeing the picture, they are asked to offer suggestions
and criticisms. If the criticisms are of sufficient importance and
are practical, we make the necessary changes. This procedure
guarantees authenticity and saves us the embarrassment from
justifiable criticism after release to the public.

The second step is a formal premiere of the picture. Even though
it may be necessary to hold up the release date for some time, the
picture is given its premiere at a national convention or meeting
of a group who are vitally interested in promoting the subject. At
this meeting, however, it is important that the picture be an integral
part of the program rather than on a commercial exhibitor's basis.
This showing gives us a good cross-section of public reaction, creates
good will for our companies, and provides an excellent vehicle for
publicizing the picture through newspapers, radio, and word of
mouth.

The third step is the public announcement. Carefully worded
copy is sent to selected trade publications whose readers will have
a natural interest in the picture. Personal letters, including copies
of the news release are mailed to a large list of individuals and
organizations throughout the country. Simultaneously announce-
ment is made to all our field offices and an article is inserted in our
house organ which reaches some 25,000 agents.

After we have carefully followed these various steps, the picture
is released publicly and a large number of requests automatically
follow.

To increase distribution further, we have equipped twenty-five,
strategically located field offices with sound projectors and screens.
These offices then follow through on their local distribution plans,
offering to project the picture to certain key groups and offering prints
without charge, to others. Furthermore, each of these offices
serves as a booking office and depository for the film. Their pro-
jection equipment, as well as prints, are inspected periodically and
monthy reports of their showings are obtained. They maintain

192 F. W. BRIGHT [j. s. M. P. E.

their own schedules and any agents in their territories who are
qualified to operate the projection equipment may borrow it without
charge.

Proof of the effectiveness of this distribution plan for public re-
leases is evidenced by the fact that one of our pictures alone was
shown to more than 20,000,000 persons before it became too dated
and was withdrawn from circulation.

Sales Training. — In showing sales training pictures, distribution
volume is, of course, secondary to proper application. Like many
businesses, we have a certain number of commissioned salesmen who
either have had no previous selling experience, or at least are new-
comers to our business. Following the war, all business employing
large numbers of salesmen will be faced with the problem of at-
tracting desirable representatives. Since the competition will be
so keen, we feel that our experience now with motion pictures will be
invaluable in this recruiting work.

Just as distribution is carefully planned before production of
public release subjects, the application of sales-training pictures is
also planned in detail before production commences. Sales-training
subjects are broken down into two general classifications: (a) basic
selling suggestions, and (b) technical sales training. The basic
selling suggestions type is used for primary training of new men, and
as refreshers for experienced salesmen. In these pictures, we in-
clude proper technique for pre-approach, approaching the prospect,
organizing the details of a selling campaign, asking leading questions,
and other details which even seasoned salesmen may neglect. Since
the subject matter is usually trite, there is a tendency to treat it
lightly, so the points are dramatized to an exaggerated degree. By
carefully planning the material in these films, they are acceptable
not only to our own personnel, but through our trade organizations,
we can attract new salesmen to our companies. Technical training
pictures for salaried representatives and more advanced agents pro-
vide an excellent medium for introducing new contracts, developing
particular sales possibilities and dramatizing the benefits as well as
the limitations of our contracts.

In the production of all sales-training pictures, we work closely
with our sales department in deciding the subject matter, preparing
the script, casting the actors, and other production details. While
sound slide films and post-recorded motion pictures have a definite
place in visual education, we have learned that lip synchronization

Aug., 1943] EDUCATIONAL MOTION PICTURES 193

gives the best results, particularly in dramatizing sales interviews
where voice inflection and timing are important. A close check is
kept on the audience's reaction to these sales pictures and suggestions
from our field representative is welcomed. Fortunately, we have
little difficulty in learning how the pictures are received by our agents.
Following nearly every showing, we receive letters, all of them ap-
parently sincere and spontaneous, since criticism is made as freely
as praise.

Personalizing Messages from the Home Office. — Because of restricted
transportation facilities, we have had to curtail, to a great extent,
visits to our field offices. Consequently, this has increased the need
for localized educational meetings of branch office personnel and
agents. By utilizing 16-mm lip synchronization we have been able
to bring educational and inspirational talks by our key men to these
local meetings. This year, for example, at our annual sales meet-
ings, which are held in some twenty-five field offices, we reduced our
traveling personnel to a minimum; yet at the same time, via motion
pictures, took approximately forty of our officers and specialists to
these meetings.

The sound projectors that we have placed in certain of our branch
offices are always readily available for both sales training and per-
sonalized messages, and since they are portable, they can be used in
not only the offices, but in hotels and other meeting places.

When we first released 16-mm motion pictures publicly, we at-
tempted to supply all requests within a short time, but soon found
that it was impossible. For example, we used nearly 600 prints of
one highway safety film, and even this large number was insufficient.
Moreover, some of our pictures are released exclusively in color and
since they run eight hundred to twelve hundred feet, the cost of
hundreds of prints is prohibitive. Rather than diminishing, the
demand for pictures increased, and we had to limit the number of
prints of each picture available. All our subjects are produced in
kodachrome from which we make black-and-white dupes, and al-
though some of them are released in color, all the sales training and
most of the public releases do a satisfactory job in black and white.
We now limit the number of prints to forty black and white and ten
kodachrome. Black-and-white prints are then deposited in our
branch office depositories and the remainder booked direct. In
cases where color-prints are distributed exclusively, the entire booking
and distribution are handled from our home office.

194 F. W. BRIGHT

Naturally there must be exceptions to this plan. Shortly after
Pearl Harbor, we produced a civilian defense picture in cooperation
with the Connecticut Defense Council and intended it to be used
only in Connecticut. However, we soon received requests from
neighboring states, and the demand increased until today we are
using sixty prints in all parts of the country. To help keep up, with
the demand for this and other pictures, after we have exhausted our
budget on the picture, we make prints available at cost to interested
non-commercial organizations. Local and state defense councils,
service clubs, colleges, safety councils, and similar groups have
purchased prints and in each case, we prepare a short credit title
showing their sponsorship of the picture.

While we are planning to maintain our motion picture program
as far as possible, the war has already made some changes and will
undoubtedly affect our distribution and application materially.
However, we hope to adhere to two main types of pictures — -public
education along the lines of conservation, health and safety; and
education of our agents and others in our sales force. We are also
experimenting with sales presentation pictures which our agents can
take directly into the prospect's home or office and which will give
him an opportunity to get and hold the prospect's attention with the
power of 16-mm motion pictures. We have already made some
progress along this line, and after the war is over, we shall be ready
to use this new application of the motion picture medium.

FIFTY-FOURTH SEMI-ANNUAL TECHNICAL CONFERENCE

OF THE

SOCIETY OF MOTION PICTURE ENGINEERS

HOLLYWOOD-ROOSEVELT HOTEL, HOLLYWOOD, CALIF.
OCTOBER 18-22, INCLUSIVE

Officers and Committees in Charge

HERBERT GRIFFIN, President

EMERY HUSE, Past- President and Chairman, Local Arrangements

LOREN L. RYDER, Executive V 'ice-President

W. C. KUNZMANN, Convention Vice- President

A. C. DOWNES, Editorial Vice-President

E. A. WILLIFORD, Secretary

C. W. HANDLEY, Chairman, Pacific Coast Section

JULIUS HABER, Chairman, Publicity Committee

Papers Committee

C. R. DAILY, Chairman
C. R. KEITH, Vice-Chairman East Coast

F. W. BOWDITCH

G. A. CHAMBERS
F. L. EICH

R. E. FARNHAM
J. L. FORREST

J. FRANK, JR.
J. G. FRAYNE
P. A. McGuiRE
E. W. KELLOGG
G. E. MATTHEWS

H. W. MOYSE

W. H. OFFENHAUSER

V. C. SHAUER

S. P. SOLOW

W. V. WOLFE

Reception and Local Arrangements

H. J. CHANON
J. G. FRAYNE

A. M. GUNDELFINGER

C. W. HANDLEY
E. H. HANSEN
J. K. HILLARD
E. M. HONAN

C. W. HANDLEY
E. HUSE

EMERY HUSE, -Chair man
M. S. LESHING
W. C. MILLER

R. H. McCULLOUGH

P. MOLE
F. K. MORGAN
H. W. MOYSE
W. A. MUELLER

Registration and Information

W. C. KUNZMANN, Chairman

G. F. RACKETT

H. W. REMERSHIED

L. L. RYDER

C. R. SAWYER

S. P. SOLOW

J. R. WILKINSON

W. V. WOLFE

R. G. LlNDERMAN

H. SMITH, JR.

195

196 FIFTY- FOURTH SEMI- ANNUAL CONFERENCE tf. s. M. p. E.

Publicity Committee

JULIUS HABER, Chairman

J. W. BOYLE G. R. GIROUX

C. R. DAILY C. R. KEITH

G. GIBSON E. C. RICHARDSON

Luncheon and Dinner-Dance Committee

LOREN L. RYDER, Chairman

A. M. GUNDELFINGER P. MOLE R. R. SCOVILLE

H. T. KALMUS H. W. MOYSE S. P. SOLOW

E. M. HONAN W. A. MUELLER J. R. WILKINSON

E. HUSE H. W. REMERSHIED W. V. WOLFE

Hotel and Transportation

A. M. GUNDELFINGER, Chairman

A. C. BLANEY A. F. EDOUART O. F. NEU

L. W. CHASE H. GOLDFORB G. E. SAWYER

H. J. CHANON G. T. LORANCE N. L. SIMMONS

L. E. CLARKE W. C. MARCUS W. L. THAYER

Projection Committee

35-Mm Programs
R. H. MCCULLOUGH, Chairman
L. R. ABBOTT W. E. GEBHARDT, JR. C. R. SAWYER

B. FREERICKS W. W. LINDSAY, JR. W. V. WOLFE

C. R. RUSSELL
Officers and Members of I.A.T.S.E. Locals 150 and 165

16-Mm Programs

H. W. REMERSHIED, Chairman

A. H. BOLT A. M. GUNDELFINGER

C. DUNNING J. RUNK

Ladies Reception Committee

MRS. C. W. HANDLEY, Hostess

There will be no special or prearranged ladies entertainment program during
the five-day 1943 Fall Conference. However, a reception parlor will be available
in the Hotel where the ladies may meet daily. The ladies are cordially invited
to attend the functions of the Conference.

TENTATIVE PROGRAM

Monday, October 18th
9:30 a.m. Hotel Lobby; Registration.
The program for the morning of this date will be announced later.

12 :30 p.m. Terrace Room; Informal Get-Together Luncheon for members, their
guests, and families. The luncheon program will be announced later.

Aug., 1943] FIFTY-FOURTH SEMI-ANNUAL CONFERENCE 197

Due to the hotel labor and food situation, it is imperative members procure
their luncheon and dinner-dance tickets at the time of registering so that the
Arrangements Committee may provide the necessary accommodations.

2 : 00 p.m. Blossom Room; General Session.

8:00 p.m. General Session; the location will be announced later.

Tuesday, October 19th

10:00 a.m. Hotel Lobby; Registration. Open morning.
2: 00 p.m. Blossom Room; General Session.
8: 00 p.m. General Session; the location will be announced later.

Wednesday, October 20th

9: 30 a.m. Hotel Lobby; Registration.
10:00 a.m. Blossom Room; General Session.

2:00 p.m. Open afternoon for recreational program to be announced later.
8: 00 p.m. Blossom Room; SMPE Fifty-Fourth Semi-Annual Dinner-Dance.
The program for the evening will be announced later. ( Dancing until
12:30 a.m.; strictly informal business dress and uniforms only.)

Thursday, October 21st

10:00 a.m. Open morning.
2: 00 p.m. Blossom Room; General Session.
8:00 p.m. General Session; the location will be announced later.

Friday, October 22nd

10: 00 a.m. Blossom Room; General Session.
2: 00 p.m. Blossom Room; General Session.
8:00 p.m. Blossom Room; General Session and Adjournment.

Conference Headquarters

The Pacific Coast Section Officers have selected the Hollywood-Roosevelt
Hotel, Hollywood, Calif., as headquarters for the 1943 Fall Technical Conference
with the following per diem rates guaranteed by the hotel management.

Room with bath, one person $3.85

Room, double bed, with bath, two persons 5.50

Room, twin beds with bath, two persons 6.60

Small suite, parlor, bedroom with bath, single or double occupancy 8.80

Room reservation cards will be mailed to the membership early in September,
and should be returned immediately to the Hotel. All booked accommodations
will be guaranteed when confirmed by the Hotel Management. Reservations
are subject to cancellation at any time prior to the Conference.

Indoor and outdoor parking facilities will be available at the Hotel head-
quarters if desired.

198 FIFTY-FOURTH SEMI- ANNUAL CONFERENCE

The Conference registration headquarters will be located in the Hotel Lobby,
and members and guests will be expected to register and receive their badges
and identification cards. The registration fees are used to help defray the
Conference expenses, and cooperation in tliis respect will be greatly appreciated
by the Local Arrangements Committee.

The identification cards will provide admittance to all sessions at and away
from the Hotel. They will be honored also at the following de luxe motion
picture theaters on Hollywood Boulevard, in the vicinity of the Hotel: Fox
West Coast Grauman's Chinese and Egyptian Theaters, Hollywood Paramount,
Hollywood Pantages, and Warner's Hollywood Theater.

Eastern and Mid-western members who are planning to attend the 1943 Fall
Conference should consult their local railroad passenger agent regarding train
schedules, available accommodations, rates, and stop-over privileges en route.
If a San Francisco stop-over is included in the trip to the West Coast, the Con-
ference Committee suggests the Mark Hopkins Hotel on "Nob Hill." Reserva-
tions should be mailed to Mr. R. E. Goldsworthy, Assistant Manager of the
Mark Hopkins.

Note. — The 1943 Fall Technical Conference is subject to cancellation if later
deemed advisable in the national interest.

W. C. KUNZMANN

Convention Vice-President

IMPORTANT

Hotel reservation cards must be re-
turned immediately. Otherwise the
Hotel cannot guarantee accommoda-
tions.

Members intending to attend the Fifty-Fourth Semi- Annual Confer-
ence should make arrangements for their railroad accommodations im-
mediately or at the latest one and a half months in advance of the Con-
ference date.

SOCIETY ANNOUNCEMENTS

MAILING OF NOTICES TO MEMBERS OF THE
ATLANTIC COAST SECTION

199

MEMBERS OF THE SOCIETY

LOST IN THE SERVICE OF

THEIR COUNTRY

FRANKLIN C. GILBERT

ISRAEL H. TILLES

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

VOLUME XLI • • • SEPTEMBER, 1943

CONTENTS

PAGE

Introduction 205

Produced by the United States Army Signal Corps

H. T. DARRACOTT 206

Some Psychological Factors in Training Films

M. E. GILLETTE 210

Training Film Production Problems R. P. PRESNEL 215

The Service Films Division of the Signal Corps Photo-
graphic Center E. COHEN 222

Animation in Training Films E. SMITH 225

Sound Recording at the Signal Corps Photographic

Center G. C. MISENER 226

Field Camera Problems R. L. RAMSEY 239

Multiple-Film Scene Selector H. W. LEASIM 246

Film Distribution J. D. FINN 251

Film Utilization B. T. WOLFF 255

Fifty-Fourth Semi- Annual Technical Conference of the

Society, Hollywood, Calif., October 18-22, 1943 263

Society Announcements 269
(The Society is not responsible /or statements of authors.)

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

SYLVAN HARRIS, EDITOR
ARTHUR C. DOWNES, Chairman

Board of Editors

JOHN I. CRABTREE ALFRED N. GOLDSMITH EDWARD W. KELLOGG
CLYDE R. KEITH ALAN M. GUNDELFINGER CHARLES W. HANDLE Y

ARTHUR C. HARDY
Officers of the Society
** President: HERBERT GRIFFIN,

90 Gold Street, New York, N. Y.
** Past-President: EMERY HUSE,

6706 Santa Monica Blvd., Hollywood, Calif.
** Executive Vice-President: LOREN L. RYDER,
5451 Marathon Street, Hollywood, Calif.
*Engineering Vice-President: DONALD E. HYNDMAN,

350 Madison Avenue, New York, N. Y.
** Editorial Vice-President: ARTHUR C. DOWNES,

Box 6087, Cleveland, Ohio.
* Financial Vice-President: ARTHUR S. DICKINSON,

28 W. 44th Street, New York, N. Y.
**Convention Vice-President: WILLIAM C. KUNZMANN.

Box 6087, Cleveland, Ohio.
^Secretary: E. ALLAN WILLIFORD,

30 E. 42nd Street, New York, N. Y.
*Treasurer: M. R. BOYER,

350 Fifth Ave., New York, N. Y.
Governors

*H. D. BRADBURY, 411 Fifth Avenue, New York, N. Y.
*FRANK E. CARLSON, Nela Park, Cleveland, Ohio.
* ALFRED N. GOLDSMITH, 580 Fifth Avenue, New York, N. Y.
*A. M. GUNDELFINGER, 2800 S. Olive St., Burbank, Calif.
. *CHARLES W. HANDLEY, 1960 W. 84th Street, Los Angeles, Calif.
*EDWARD M. HONAN, 6601 Romaine Street, Hollywood, Calif.
*JOHN A. MAURER, 117 E. 24th Street, New York, N. Y.
**WILLIAM A. MUELLER, Burbank, Calif.

**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood, Calif.
**H. W. REMERSHIED, 716 N. La Brea St., Hollywood, Calif.
* "JOSEPH H. SPRAY, 1277 E. 14th Street, Brooklyn, N. Y.
**REEVE O. STROCK, 195 Broadway, New York, N. Y.

*Term expires December 31, 1943.
**Term expires December 31, 1944.

Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.

Publication Office, 20th & Northampton Sts., Easton, Pa.

General and Editorial Office, Hotel Pennsylvania, New York, N. Y.

Entered as second-class matter January 15, 1930, at the Post Office at Easton,

Pa., under the Act of March 3, 1879. Copyrighted, 1943, by the Society of Motion

Picture Engineers, Inc.

SYMPOSIUM ON THE
TRAINING FILM ACTIVITIES OF THE U. S. ARMY

Prepared by Members of the U. S. Army Signal Corps, Army Service

Forces, and Presented at the Spring Meeting of the Society, at the

Hotel Pennsylvania, New York, N. Y., May 6, 1943

The papers constituting the Symposium, in the order of their pub-
lication in this issue of the JOURNAL, are as follows :

"Produced by the United States Army Signal Corps" ; Capt. Halvor T. Darracott,

U. S. Army Pictorial Service, Washington, D. C.
"Some Psychological Factors in Training Films"; Col. M. E. Gillette, U. S.

Army Signal Corps Photographic Center, Astoria, Long Island, N. Y.
"Training Film Production Problems"; Lt. Col. Robert P. Presnel, U. S. Army

Signal Corps Photographic Center, Astoria, Long Island, N. Y.
"The Service Films Division of the Signal Corps Photographic Center"; Lt. Col.

Emanuel Cohen, U. S. Army Photographic Center, Astoria, Long Island, N. Y.
"Animation in Training Films"; Major Ellis Smith, U. S. Army Signal Corps

Photographic Center, Astoria, Long Island, N. Y.
"Sound Recording at the Signal Corps Photographic Center"; Major G. C.

Misener, U. S. Army Signal Corps Photographic Center, Astoria, Long Island,

N. Y.

"Field Camera Problems"; Capt. Ray L. Ramsey, U. S. Signal Corps Photo-
graphic Center, Astoria, Long Island, N. Y.
"Multiple Film Scene Selector"; Capt. Harry W. Leasim, U. S. Army Pictorial

Service, Washington, D. C.
"Training Film Distribution"; Lt. James D. Finn, U. S. Army Pictorial Service,

Washington, D. C.
"Training Film Utilization"; Mr. Boyd T. Wolff, U. S. Army Pictorial Service,

Washington, D. C.

205

PRODUCED BY THE UNITED STATES ARMY SIGNAL CORPS

CAPT. HALVOR T. DARRACOTT*

Through the Army Pictorial Service the Signal Corps serves as
teacher, historian, and ambassador for the United States Army.
Day by day demands for motion pictures of the combat zones, train-
ing films, film-strips, English versions of United Nations training films,
special films for morale purposes are growing by leaps and bounds.

From a small group of officers and civilians and two training film
production units, the Army Pictorial Service has grown into an
organization including photographers spread throughout the world,
as well as a major studio organization for the production of training
films. The range of activities covered by this organization is de-
cidedly comprehensive, including a good many contacts that are
comparatively little known to the general public. The Army profits
greatly by the thorough cooperation of the photographic and motion
picture industries within the United States.

Proper operation of this far-flung Army Pictorial Service has been
planned on a systematic and functional basis. The Army Pictorial
Service has been set up as a separate service within the Office of the
Chief Signal Officer. The Chief of the Army Pictorial Service also
is a member of the Army Pictorial Board, which decides which
organization within the three main divisions of our modern army —
the Army Air Forces, the Army Service Forces, and the Army
Ground Forces — will undertake the various photographic projects,
and who will be responsible for their completion as well as for ob-
taining the necessary trained personnel to carry out those projects.
Three branches make up the Army Pictorial Service: the Motion
Picture Production Branch, the Pictorial Administrative Branch,
and the Field Activities Branch. Each of these branches in turn
has several sections, the numbers and functions of which are de-
termined by the branch.

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Pictorial Service, Washington, D. C.

206

PRODUCED BY U. S. ARMY SIGNAL CORPS 207

The Motion Picture Production Branch is responsible for the
procurement and production of all training films used by the three
divisions of the Army. The Service concerned requests from the
Chief of the Army Pictorial Service a training film on a particular
subject. The project is set up, the "go ahead" signal is given, and
the Motion Picture Production Branch decides whether or not the
picture is to be produced commercially or by the Signal Corps
facilities. In any event, by whichever method used, the film, in its
final form, is viewed by the Chief of the Service concerned, and, when
given his approval, is handed over to the Training Film Distribution
Section for distribution and proper utilization within the three
divisions of the Army.

The Motion Picture Production Branch also is responsible for the
staff supervision of the procurement of film bulletins, film-strips,
and special war films such as those being produced by the 834th
Signal Photographic Detachment, which is showing the background,
history, and effect of the present world conflict upon the conquered
nations. Under the Special Projects Section films are produced at
the rate of at least one per month for distribution to the war workers
of the United States, who are shown how their particular jobs tie
in with the war effort and what important parts they are playing in
this conflict. Included in the Army Pictorial Service is the Combat
Film Section, which is responsible for the assembling and distribution
to the Bureau of Public Relations of the War Department of films
exposed by the motion picture photographers of the Signal Corps
in the combat zones. Film is received from the combat zones, de-
veloped, printed, viewed by the photo news board of the War De-
partment, and classified according to its subject matter; and that
which is permissible to be released to the general public is turned over
to the Bureau of Public Relations for distribution to the newsreel
services. This service is provided the newsreel companies on an
exchange basis. Such footage as is shot in the combat zones by their
own photographers as is needed by the Signal Corps for stock shots
is turned over to the Signal Corps free of charge.

A special development laboratory unit known as the Signal Field
Mobile Laboratory Unit has been organized to go into the theatre
of operations and carry portable 35-mm development equipment.
Taking the motion picture film exposed by the Signal Corps combat
photographers in the theater of operations, this unit develops it and
makes a print for the Commanding General and staff of that theater

208 CAPT. H. T. DARRACOTT [J. S. M. P. E.

to show the reaction of their troops to the present situation and how
their work can be improved. Prints of these films will be returned to
the United States to the Combat Film Section for distribution to the
newsreel companies after classification, thus shortening the period
between the time motion picture film is exposed in the combat zone
and the time it is received in the United States for dissemination
through the newsreel organizations.

The Field Activities Blanch of the Army Pictorial Service con-
tains the F-Mail Section, which is responsible for the utilization of
microfilm to reduce to minute dimensions in bulk letters to and from
our soldiers in the combat zones overseas, thus speeding up the news
from the soldiers in the field to their loved ones at home or, from
those at home to the soldiers on the firing line. Avoiding long delays
of mail sent by other and less rapid means, this service contributes
greatly to the morale of both the troops and those at home. The
idea of this type of service originated in the Franco-Prussian War
and was but recently revived. The modern system was first put
into effect by Airgraphs, Ltd., which established microfilm letters
foi the British troops.

In May of 1942 the Signal Corps contracted for a similar service
to be established for American troops under the name of F-Mail.
Shipment of F-Mail letters in reduced or enlarged form is handled by
the American Postal Service of the Adjutant General's office, while
the reducing to microfilm and the subsequent enlargement to readable
letters is done by personnel of the Signal Corps. Far-flung stations
for the handling of the service have been set up in areas where Ameri-
can troops are stationed. Close cooperation is maintained by the
Signal Corps with the British Airgraph Service, and arrangements
have been made for F-Mail Service for the United States Navy and
Marine Corps.

Signal Corps motion picture photographers use standard equip-
ment, both 16- and 35-mm, and cameras of standard commercial
design. The Army Pictorial Service has concentrated its efforts
upon modifying the equipment, rather than designing new equipment
to make it mobile and easily handled, and to simplify it in accordance
with Army requirements. The Equipment Section of the Field
Activities Branch has been responsible for the development and
modification of standard motion picture cameras for use in the field.

The custodial responsibilities of the Army Pictorial Service are
centered in the Still-Picture Section which has the celebrated motion

Sept., 1943] PRODUCED BY U. S. ARMY SIGNAL CORPS 209

pictures and the still-picture file containing thousands of films shot
during the First World War as well as famous collections of still
photographers, such as Brady, of Civil War fame. Close cooperation
with the United Nations Film Committee, especially with the
British and Russian photographic Service, has resulted in the ad-
dition of a great many foreign training films in the stock of the Army.
In return, American training films are being made available to others
of the United Nations. Sound-tracks in the appropriate languages are
added when necessary.

SOME PSYCHOLOGICAL FACTORS IN TRAINING FILMS*
COL. M. E. GILLETTE**

There are a number of purely psychological factors involved in
making all types of motion pictures. Several of these, if properly
recognized and utilized, prove to be powerful and useful tools in
making training films. Five of the most important of these factors
will be briefly discussed in this paper.

(1) The first is the "defect" in human vision known as the per-
sistence of vision. This effect is responsible for our ability to see
motion pictures. The eye retains the image of an object for ap-
proximately one- tenth of a second after the object has been removed.
The removal and replacement of an image in the same position at a
rate of more than ten times per second is seen by the eye as a single
continuing image. In sound-films a series of twenty-four pro-
gressive images, or still pictures, per second flash upon the picture
screen. When examined individually each of these twenty-four
pictures is a "still" picture. If they are examined individually
in a series, they show a progression of movement of the objects in
gradually changing or advancing positions. When a series is pro-
jected upon the screen, it provides an illusion of motion. Use of this
principle with lifeless objects or illustrations makes it possible to
give an illusion of life and action to inanimate things.

(2) The second factor may well be termed "persistence of mental
image" as distinguished from persistence of vision. Extensive use
is made of this principle; in fact, it is the basis of story telling in all
modern motion pictures. Motion pictures would be almost im-
possible or at least extremely unsatisfactory if producers were denied
its use, as production costs would be prohibitive. It is the principle
of connecting a number of scenes, photographed separately and at
different times and places, into a continuity thus making it possible
to tell a story. It is not widely understood outside motion picture
fields, and even there the principle is not often expressed but is

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Signal Corps Photographic Center, Astoria, Long Island, N. Y.
210

PSYCHOLOGICAL FACTORS IN TRAINING FILMS 211

rather felt. It is used so widely and in so many different ways in
film production that a full discussion of it would be beyond the scope
of this paper.

For illustration, when a film producer wishes his audience to identify
the action as taking place in New York City, he will flash upon the
screen a general view of the skyline of lower Manhattan, a view of
Brooklyn Biidge, The Empire State Building, Times Square, or some
other well known landmark. Following this scene may come a view
of some side street (a Hollywood replica, perhaps); then the front
of a house (also a replica or a miniature) ; then the inside of a living
room showing four persons sitting around a card table (a Hollywood
studio scene); then a front view, medium close-up, of one of the
players; and finally a close-up or an insert of the cards in the hands
of a player — perhaps five aces! Individually, these scenes may have
been made many miles apart, at different times, perhaps a year
or more apart. Yet when presented in a film the aggregate mental
image they create is the impression that the time is the present and
that a man in a little house on a side street in New York holds five
aces. Thus the director has created the background location and
opening for his story, which persist until he wishes to change the
locale by introducing another sequence of a similar nature.

In the entertainment film, In Old Chicago, extensive use was made
of miniature and other camera trick devices. The general view of
burning buildings from across the roof tops was a scene of a mini-
ature town which had been set on fire. Street scenes were made
outdoors on the studio lot. Views of the action inside the building
were made on the studio stage; likewise, the close-up action of
individuals standing against the sides of buildings were probably of
studio origin. Examined individually in their local backgrounds,
these scenes are not particularly impressive, but examined col-
lectively after assembly by expert hands; they built an overall
illusion of a major catastrophe, taking the audience into intimate
details in such a manner that the audience did not feel any dis-
continuity or break in the overall action as the screen images rapidly
shifted from exterior to interior close-ups, etc. The intermingling
of scenes of miniatures and scenes of full-size figures and buildings
was performed in such a manner as to obtain the overall illusion
of reality, and the audience "saw" the people in the midst of the great
fire. The persistence of the mental image established by the long
shots carries through the showing of the close-ups and medium shots,

212 COL. M. E. GILLETTE [j. S. M. P. E.

and, on the other hand, the mental images of the close-up action
are carried over into the long views in the minds of the audience.

The interest-holding qualities and audience-participation in the
midst of the action is wholly dependent upon the skillful use of this
principle by the director and the film editors. In the motion picture
industry scenes used to orient the audience as to where the action
is taking place are known as establishing shots. This type of shot is
very essential in instructional training films.

(3) The third factor is the principle of motion. A feeling of power
results if an object starts at the center of the screen as a small image
in the distance and rapidly approaches dead center on the screen
until it finally fills the screen completely. When an object fills the
screen initially and rapidly diminishes in size into the distance, a
feeling of loss of power or relaxation results. Scenes photographed
at a very low angle showing rapidly approaching action give a feeling
of power.

A feeling of smoothness and continuing action can be obtained
by using a series of scenes in which the movement is uniform and
steady, and always in the same direction. The nearer the movement
to the horizontal the greater is the effect.

An effect of greatly increased speed and excitement may result
from action moving across the screen ; the camera follows the action
and the backgrounds appear to be moving. This is especially true
of "pan" shots. For example, consider scenes showing a baby
crawling, a man walking, a man on a bicycle, a man on a galloping
horse, and a fast airplane. Arrange the scenes in the order named,
starting with a fairly long scene of the baby crawling, and progres-
sively shorten the length of each scene with the airplane scene the
shortest in the series. The psychological effect is that of acceleration.
Deceleration can be accomplished by the reversal of the example just
given.

An object approaching diagonally down from a corner or the top
of the screen will frequently produce the feeling that the action is
taking place on a slope inclined toward the observer. This effect
results from placing the camera high and tilting it downward. Like-
wise, an object coming from the bottom of the screen and moving
upward frequently gives a feeling that the object is climbing a slope.
\When the camera is placed on the top of a hill and tilted down-
ward,fthe action will appear to be taking place on level ground.
Likewise, a camera placed at the bottom of a steep hill and tilted up-

Sept. , 1943 ] PSYCHOLOGICAL FACTORS IN TRAINING FILMS 213

ward will show the action as if occurring on level ground. At the
top of the hill where the action disappears on the crest, it will appear
to be moving down hill. A side position for the camera which
profiles the action and the hill is the only position in which slope can
be shown. In any position other than a profiling position, the
camera definitely flattens the terrain.

A series of very short scenes or a composite scene showing action
moving in many directions gives a feeling of confusion. Long
scenes from the same viewpoint produce a reaction of impatience or
slowness. Inadequate scene length in successive scenes produces
a feeling of frustration due to the fact that the audience does not have
an opportunity to understand what is occurring.

(4) The fourth psychlogical factor is atmosphere. The lighting
of a scene — the brightness or lack of brightness, or the mood
established through the placing of light, and the use of light and
shadow differences in the scene — may create a definite reaction in an
audience. In entertainment films, mystery pictures, for example,
are usually photographed with low key lighting to assist in creating
an illusion of mystery and the unknown. Comedies are generally
photographed in high key; the scenes are bright and clear to assist
in creating an illusion of lightness. Deep, murky shadows across
a scene can be used to obtain a reaction of depression or suspense. A
flat, muddy appearing scene made under rainy or dark light con-
ditions gives a depression reaction.

Another factor is the environment or the surroundings of the
center of action. Obviously, a refuse dump or paper-littered drill
field has no place in the background of a film showing snappy drill.
Incongruous backgrounds destroy the effect and validity of a scene.
A shot simulating battle conditions made on the parade ground, for
example, is greatly weakened if barracks show in the background.
Likewise, a group of spectators or automobile traffic in the back-
ground will effect the same result.

Natural sound recordings can be used to supplement or reinforce
the emotional reaction of a scene. When so used they become part
of the ' 'atmosphere" of the scene. On the other hand, incongruous
sounds may seriously mar or destroy the desired effect or validity
of a scene. Twittering birds, distant laughing, a train whistle, and
similar sounds may mar the desired effect. The lowing of cattle at
the instant a platoon leader commands "charge" will completely
destroy the effect desired and turn a serious situation into a comedy.

214 COL. M. E. GILLETTE

(5) The fifth factor is the principle of comparison. In the enter-
tainment field, in order to bring about the desired emotional effect,
it is common practice to alternate pathos and comedy as relief
mediums. In training film it is deadening and interest-destroying
to hammer continually on "do this," "do that," etc., without pro-
viding some means of relieving the tension of the audience. I
do not, however, mean to infer that we should inject comedy or
pathos as relief mediums into training films.

There are many ways of using this principle of comparison in the
production of training films although they are not as obvious as
the above examples. There are several methods of obtaining this
relief without injecting irrelevant or distracting factors into a film.
In a film that is basically a "what" or a "how" type of film, we are
often able to inject a little of the "why" into the film to relieve tension
and as an interest-arousing and a holding factor. The use of objects
or ideas close to common experience may often be properly used
to draw comparison and illustrate something otherwise abstract and
thus relieve tension.

In films showing the duties of a gun crew in placing and serving
the gun, relief can be provided by showing the result of such firing.
In some types of films the nature of the action itself provides the
necessary relief through the shifting of background situations or of
action. While such relief is desirable and necessary, it is difficult
to prescribe a definite formula as to its use, or to provide it without
introducing undesirable factors. The use of this principle requires
considerable thought during the planning and production stages,
and wherever it can be used effectively with no undesirable results,
it should be so used.

It may be safely said that sound-films can be used to arouse and
influence all the human emotions, in practically the same way that
similar real-life situations would influence an individual. The
settings and lighting may depress or raise the spirits; movement on
the screen may thrill or frighten; scene selection may transport us
into distant lands or into the past. Any of our numerous emotions
may be played upon by suitable scene action, scene selection, light-
ing, sound, etc. A complete discussion of these factors is impossible
here. The examples mentioned should, however, indicate that this is
a very broad and important field, and an understanding of the prin-
ciples is necessary so that we may avoid introducing undesirable or
unwanted reactions while striving to create those that are desirable.

TRAINING FILM PRODUCTION PROBLEMS*
LT. COL. R. P. PRESNEL**

In the Army, in the production of training films, we have a special
phenomenon, and that is the making of motion pictures without
artistic temperament. I think it is something new under the sun.

They say that war is a great leveller. You never hear an Army
picture director raise his voice and shout or complain because every-
thing is not exactly as he wishes it. Our camera units are also groups
in which many sentences begin and end with the word Sir. We are
fighting the war with scenarios, using words for ammunition. We
have 90-mm adjectives, 155-mm verbs, 40-mm automatic nouns.
And our theme song is, "Praise the Lord — and Parse the Ammuni-
tion." Our cameramen are mostly sergeants and our assistant
directors are often corporals. They may carry gas masks and eat
out of mess kits. They may drill mornings and nights to be ready.
This is a new kind of motion picture making.

Training film production is the assembling of film into sequences
that will teach military subjects to large audiences of average intel-
ligence. All training films are aimed at the soldier in combat, or at
least in the theater of operations, and are designed to teach him the
use of his weapons, his equipment, the care of his health, and certain
principles of tactics and individual care. For this reason, the close-up
is used to the best advantage. In a sense the films are educational
films, but with a different accent. The accent is speed and the ever-
present reminder of danger. We have to put our message across
with a sharp impact. That is one reason why we are in the Signal
Corps : we have a message to deliver.

Most of the Army training films are made in the field, by which
we mean camps and Army schools scattered throughout the country.
In Astoria we have a large and excellent studio, an historic studio, of
which we are very proud, but only a small percentage of our pictures

* Presented at the 1943 Spring Meeting at New York, N. Y.
!* U. S. Army Signal Corps Photographic Center, Astoria, Long Island, N. Y.

215

216 LT. COL. R. P. PRESNEL [j. s. M. P. E.

can be taken indoors, on our stages. We can't maneuver tanks or
lay down an artillery barrage, or stage cavalry movements anywhere
but out in the desert, or range, or on practice grounds.

Our crews travel in camera trucks. We have done some experi-
menting in the building of these camera trucks, for compactness and
economy of space, and camera equipment comes under the category
of delicate instruments. The equipment must be carefully packed,
cleaned, and cared for in the field so that it will continue to function.
There are some fifteen or sixteen camera crews ranged across the
country right now, and this represents a quarter of a million dollars
worth of equipment that must be transported and taken care of.
This is quite an item and quite a responsibility. It becomes even
more complicated when sound equipment is added, all of which must
also be transported and maintained.

We can not and do not send out great caravans to install set-ups
for shooting outdoors. The average camera unit consists of five to
seven men with an officer in charge. Officer, sergeant, privates,
all bear responsibility. They must constantly improvise and meet
the most unexpected events with American ingenuity, just as men
in fox-holes and men in tanks are doing.

That is why we have no time for temperament. All have to work
together. Working in the field, often under the most adverse con-
ditions of weather and equipment, our camera units carry out the
dictum of that famous general on Bataan: "We must make the most
of the little we have."

I do not mean to imply that the Army does not give its crews the
best equipment available, but rather that not too much is available
anywhere these days, as you well know. A Signal Corps Camera
Unit may be one in which a first cameraman — we do not have nearly
enough of them — will also be his own operator and very often carry
his own camera. Our directors do not have chairs with their names
painted on them, and our script clerk very often is a utility man or
assistant director to boot. He will take notes with one hand and
carry a battery with the other.

In the field, our crews can not sit by waiting for the right weather
or for light of exactly the correct quality. Colonel Gillette has given
us a motto, "One training film on the screen today is worth ten on
the screen next year." We have no time to lose — not a minute.

Our job is to teach men how best to protect themselves and carry
out their duties in the face of peril. That means that photographic

Sept., 1943] PRODUCTION PROBLEMS 217

excellence is not a prime consideration. And yet, we know that the
best training films are those that are the best photographed and
directed. If we want to teach other men to do their jobs well, we
must demonstrate to them that we too are doing our jobs well.
And, of course, we have a critical audience; our training film must
compete for attention or admiring respect with the entertainment
films that are shown nightly in the same camp. It may be said that
what we have here is the problem of turning out pictures comparable
in skill and finish with the best modern products of Hollywood, under
conditions that in many ways compare to those that prevailed in the
days of the motion picture's infancy.

This fact, that we are getting back to essentials in this work of ours,
is perhaps the most outstanding. War is always a matter of getting
back to essentials. So, in organizing our work and in training the
men who are to make the training films, we have undergone a process
of unlearning and reeducation for ourselves.

Many of the men in our units enjoyed reputation and success as
writers and technicians in civilian life. They have come to us with
complete knowledge of how to make pictures "the Hollywood way,"
but in the Army we are up against something different. The main
idea in Hollywood technique is to entertain. When these same men
write and shoot training films, their purpose is to teach. It is a
different approach.

Obviously, the appeal of the training film is not to the emotions or
even to the imagination, but to the mind. The training film must
be written in simple language, so simple that any soldier may grasp
its teaching. It must move quickly, yet must make its point very
thoroughly without seeming repetitious. Men brought in to view
these films may have spent hours marching or carrying out fatiguing
duties. They may not always be as alert and attentive as they
might otherwise be. The pictures may have to be shown more than
once, and so they must not include scenes or speeches that on an-
other showing will lose their original effect. For example, when we
sought to lighten our films by the use of humor, we soon discovered
that the jokes or gags did not "go over" very well the second time
and third time. Similarly, suspense is not a very useful device for
us. How to keep our films lively, how to bid for attention, and how
to hold it, in the face of such restrictions — that is what our writers
and directors are up against. How to climb a telephone pole, how
to splice a wire, how to build a ponton bridge under fire, how to clean

218 LT. COL. R. P. PRESNEL [J. S. M. P. E.

a gun, how to avoid malaria, how to keep your feet clean — it does not
sound like very interesting material, does it? But it is, and it is
important that men know these things. Their lives depend upon it.

We give special orientation courses to our writers, designed to
initiate them into the secrets of good teaching. We have lectures
by psychologists who have studied the best methods and principles.
It is not easy to stir or delight an audience with an exposition of how
an anti-aircraft gun is put together. Yet that is a fundamental part
of our job. We call such pictures "nut-and-bolt" pictures. Given
the job of telling about the bolt mechanism of the M-l rifle, our
writer has no opportunity to wax lyrical. But if the subject is thor-
oughly understood by the writer and is well organized by him, its
exposition will be clear and interesting to the man who is to use the
rifle and who appreciates how much depends upon his knowing how
to fire it.

The scenario is especially important, and strict adherence to it is
one of our production problems. We can not, as so often happens in
Hollywood, rewrite our stories on the spot. We can not stop our
shooting for story conferences. The branch of service for which
we are working has given us a story, and we stick to it. That is
because every line, every scene, every detail presented in our film
has been carefully gone over and approved by experts. To make
changes in the scenario would mean to go back through channels
for approval. The fullest cooperation exists between the branches
and us in the preparation of the scenarios — and we stick to the tech-
nical content because it represents the best thought of the Army on
the subject.

Our writers travel to the service schools and often take courses in
the subjects about which they are to write. They accompany troops
on maneuvers, they watch experiments, they learn at firsthand, so
that they can teach vividly and accurately. Technical advisers,
men highly schooled in specific subjects, are always at hand. The
writing of a training film is a matter of teamwork — hard, pains-
taking teamwork.

We thus observe our writers working side by side with military
experts on poison gases, bombs, tanks, weapons of every kind. It
has been one of the tasks of our writers, who speak the language of
motion pictures in all its technical terms that sound so mysterious
to outsiders, to put across their ideas to these men who are specialists
in the various phases of military activity. We are frequently asked

Sept., 1943] PRODUCTION PROBLEMS 219

to supply these technical advisers with a glossary of what is meant
by "dolly shots," "pans," "wipes," and "dissolves."

Recently a military adviser suggested that a certain scenario sub-
mitted to him was, in his words, "pretty rugged," because he read
so many directions calling for "shooting from the rear," "shooting
from above," and thought we meant shooting with bullets rather
than with film. He was considerably relieved when we explained
that we did not intend to wipe out half the men assigned to us as
actors. A very friendly and intelligent technical adviser not used to
Hollywood talk, obligingly brought forth a T-square when the
writer informed him that he would like another angle on a script.

We have succeeded, nonetheless. Indeed, sometimes we are so
successful in winning over and educating these technical advisers in
matters that have to do with the making of motion pictures, that we
find ourselves with another problem on our hands : technical advisers
succumb to the widespread temptation and wish to become motion
picture producers themselves. This calls for the utmost tact on the
part of those assigned to work with them for the temptation gets
into the blood stream sometimes and the technical adviser becomes
a very sick man.

In our films the organization of material is not our only problem.
If Hollywood has a language of its own, so has the Army. We have
had to learn how to speak Army language and also how to make Army
language clear to our civilian soldiers. Much of the material we have
put on film has already been set down in field manuals. The lan-
guage of these manuals is very precise, but when read aloud it does
not make the most interesting kind of narration. It "talks like a
book." We have to tackle the job of translating this most formal
and precise field manual language into everyday speech that will
make the point more effectively and still be correct. Our films must
be "racy" in speech and still have dignity, because they speak with
the impersonal voice of the United States Army, whether our narrator
is a tough old sergeant or a brigadier general.

The shooting of a training film is even more a matter of teamwork.
It begins with preparations and explorations in which we try to fore-
see just what our crews will need or have to contend with from the
moment they leave the post until the last foot of film is shot. It is
like planning a campaign in miniature.

In order to obtain our actors, and, even more important, in order
to obtain the military materiel — the tanks, the planes, the motor

220 Lx. COL. R. P. PRESNEL [j. S. M. P. E.

vehicles, the guns, the jeeps, ammunition, chemicals — that we re-
quire when filming a picture, we must initiate requests through the
appropriate channels. I need hardly tell you that we do not have
idle tanks and idle guns and idle men standing around and waiting
for us. Every gun, every tank, every man is busy; it is not easy
for us to obtain their services, and when we do get them, we have to
make efficient use of them without any loss of time. If we have been
given use of a company of men today, we can not send them back
because the sky is cloudy, and expect them on hand tomorrow.
They may be scheduled for maneuvers tomorrow, and today's cast
may be on its way overseas before the month is out. That means
that if retakes are needed, that will not be a simple matter either.
We have to shoot right the first time; the same rule that applies for
the infantry man aiming his gun at the enemy applies to us also.

We have found it the best policy to use soldiers from the ranks as
our actors, so that the men who see the pictures will most readily
identify themselves with the men on the screen. We do not use the
handsomest soldiers, or the trimmest, or the most stalwart or intelli-
gent looking soldiers, but ordinary men of all racial types. We
were considerably embarrassed, however, on one occasion, when one
of the southwestern camps supplied us with a contingent of Japanese-
American soldiers to enact an important scene. They were fine
fellows and good soldiers and loyal to everything American, but we
did not know how the rest of the Army would take instruction from
them. It happened to be a scene in which poison gas was depicted,
however, and so we were able to put them ah1 in gas masks and
get away with it. When these man had their masks on, we had no
trouble with them in the matter of their stealing side glances toward
the camera, but elsewhere we constantly have to work with camera-
shy actors. Nevertheless, we think it worth while to use ordinary
soldiers. These are pictures by soldiers, with soldiers, for soldiers.

It is not only the camera field units that have special problems.
Our sound units have even greater difficulty, especially since planes
are so likely to be flying over the camps where our films are being
made. One director said to me, "If it isn't a plane, it's a train; and
if it isn't a train, it's artillery on the range or target practice — and if
if isn't target practice, it's crickets, and the damn crickets never
stop!"

We have been short of such mobile sound units but their number
has been increasing, and more and more we are being able to use

Sept., 1943] PRODUCTION PROBLEMS 221

live sound to the heightened effectiveness of our film teaching.

This is a war of rapid change, of learning by experience. Pro-
cedures, weapons may change overnight, and we may find ourselves
with a picture half finished and suddenly obsolete. Our films must
be correct in every detail. We can not teach men methods that have
been disapproved. You may be able to cover up a mistake in a
historical picture in Hollywood. But we can not cover up anything.
We must not make any mistakes. So we are frequently forced to
very complicated expedients in order to save our films and keep them
abreast of changes. We are in a race against time, but so is the
whole Army, and we are only trying to keep up. The faster we make
our pictures, the quicker our millions of men will be brought up to
date in their training, ready for the task we all face.

Another aspect of our work is psychological preconditioning for
battle. So far as possible, we try to simulate actual combat con-
ditions and show the men that what they are learning in the camps
will be applied in the moments of stress and crisis that await them.
It is not the chief function of training films to be inspirational; they
are not meant for propaganda, yet this element is not lacking al-
together. We not only show men how to use weapons, but we sug-
gest to them the urgency of their knowing how to conduct themselves
properly with them. Among the training films we have made is a
series for the Army Ground Forces in which various psychological
problems that have to deal with fear in battle, and discipline, have
been dramatically presented. I am proud to say that these films have
won commendation from the War Department who told us that they
considered them worth ten divisions to our Army.

THE SERVICE FILMS DIVISION OF THE SIGNAL CORPS
PHOTOGRAPHIC CENTER*

LT. COL. EMANUEL COHEN**

The subject of this paper concerns a little known but rapidly
expanding activity of the Signal Corps Photographic Center — the
Service Films Division. The name Service Films, derived from the
functional nature of the special films produced, best describes the
type of motion pictures that are designed to provide a special service
to the Army at large.

The Service Films Division was organized to consolidate all film
activities which by their special nature could be classified as "service"
and not "training" films. To distinguish between the two is difficult
because it is hard to say that service films do not train, because they
do; but their primary function is to disseminate information through
the medium of motion pictures more effectively than through printed
pamphlets and mimeographed letters.

Modern mechanized war changes so swiftly and new equipment is
developed so rapidly that a film service equally as flexible was needed
to transmit, visually, data on new weapons, equipment, and tech-
niques to branches of the Army that could utilize the information to
best advantage. Since training films are based upon doctrines
developed over a long period of time, service films are designed to
disseminate quickly new doctrines to Staff Officers whose task it is to
evaluate every piece of new equipment and fighting technique and
decide in the shortest possible time what equipment and methods
are to be adopted by our fighting forces. Distribution of these
service films is not limited to this country but is extended overseas
for the information of officers and men in combat areas. Some
service films show the various types, capabilities, and effectiveness
of the enemy's weapons. Prints of this type of technical reel would
be distributed to advanced echelons in combat zones as well as to
ordnance officers in this country. By this means troops overseas,

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Signal Corps Photographic Center, Astoria, Long Island, N. Y.
222

SERVICE FILMS DIVISION 223

soon to face the enemy, are given a realistic demonstration of the latest
types of weapons the enemy uses. Applying here the theory that he
who is forewarned is forearmed, our officers and non-coms can use
this information to devise defenses against these weapons and also to
reduce the effect of shock encountered by troops who would have
had to face a type of fire that they had no idea the enemy possessed.

For some time, high-ranking officers of the Army Ground Forces
and the Army Service Forces had been considering ways and means
of improving the use of chemical mortars — small cannons that fire
smoke and other chemical shells. The officers were not satisfied
with the number of men and pieces of equipment that were required
to blanket an area with a smoke or gas screen. Numerous combina-
tions were discussed pro and con and tested. Finally, the 'Tour-
Point-Two Chemical Mortar," with its small complement of men
and machines, looked most promising, so it was tested, not before a
group of assembled staff officers on leave from their official duties,
but before motion picture camera crews with their Eyemos and
Mitchells which photographed every detail of the test far better
than individuals could observe at firsthand with the naked eye. Not
only was much time saved for a score or more of the Army's leading
ordnance, chemical warfare, tactical, and other experts, but at the
same time a permanent record was made that could be studied and
restudied. This film also eliminated the necessity for restaging the
tests at additional expense for those who could not attend because
of the pressure of more important duties. As a result, the Army's
eventual adoption of the Four-Point-Two Chemical Mortar was in
no small part due to the film demonstration, which forms part of
what is known as Film Bulletin No. 46.

Other bulletins and special productions made by the Service Films
Division have included such subjects as "Battle Firing." This bul-
letin showed our men a new and revolutionary technique of firing
small arms. To date a large number of analytical tests have been
photographed for the various service boards of the Army such as the
Ordnance Board at Aberdeen Proving Ground, where new types of
American, allied, and enemy guns, bombs, armor-plate, jeeps, and
trucks undergo continuous tests to develop the best arms and equip-
ment for America's armed forces. Camera teams ate stationed at
these boards to make the tests when ordered. The commentaries
of these bulletins stress the significance of the various scenes as they
apply to training. Errors as well as proper procedure are pointed
out in the narration.

224 LT. COL. E. COHEN

Another activity of the Service Films Division is the Special
Productions Branch. This unit makes special films ordered by,
for example, the Secretary of War, who may request a film on the
manpower resources of the United States; the Chief Signal Officer,
who may wish to present a film report on the activities of the Signal
Corps; or the Commanding General of the Army Service Forces,
who may order a film made to demonstrate the huge supply problem
involved in equipping and transporting America's first AEF to
North Africa. These pictures are made within a given time limit,
mostly from the extensive resources of the military stock film files
of the War Department Central Film Library, also a branch of the
Service Films Division.

The Central Film Library maintains a carefully edited file of
some ten thousand cross-index cards describing the contents of
more than two million feet of training films, film bulletins, special
productions, film shot by the Signal Corps cameramen in combat
areas, and miscellaneous military footage procured for use in official
War Department pictures. These stock shots are used to expedite
production, and represent the most extensive collection of indexed
military subjects, edited and classified by specific types, available
for immediate use. For example, if a piece of film were received
by the library showing ninety-millimeter anti-aircraft guns firing
at enemy planes in Tunisia, it would be indexed from a master editing
sheet ("dope" sheet, which we make up upon viewing the film) as
follows :

1. North Africa — Tunisia — Ninety Millimeter A A gun
ASF — Ordnance — Ninety Millimeter A A gun
AGF — AA Command — Ninety Millimeter AA gun
German — Air force — light bomber — Junkers Eighty-eight,

To summarize, the Service Films Division is comprised at present
of branches that include the Film Bulletin Branch, which produces
technical magazine reels of tests and demonstrations; the Special
Productions Branch, which makes what the name implies; and the
Central Film Library.

Plans have been made also for the expansion of the Service Films
Division to include still further developments in the use of film to
disseminate information jointly with other services, such as the
Navy, Marines, and Coast Guard. As yet, no details can be given,
but it will be an important step in the use of film in the War Effort.

ANIMATION IN TRAINING FILMS*
MAJOR ELLIS SMITH**

Animation is used in military training films when live-action
photography is impracticable or impossible. Disturbing or dis-
tracting elements encountered in live action are eliminated, resulting
in a clear, vivid portrayal unhampered by non-essential details.

Examples of the most frequent uses of animation are :

(1) Operating cross-section views of machine parts, such as the
internal workings of guns, the movement of pistons and valves in
internal combustion engines, the identification of parts, the inter-
relation of elements, and schematic chemical or physical processes.

(2) Tactical maneuvers covering large areas of terrain. Views
from any altitude can be represented.

(3) Visualization of intangibles: gases, electricity, magnetism,
molecular phenomena, thermodynamics, ballistics, microscopic ac-
tivity, can be effectively demonstrated by animation.

(4) Animated graphs, charts, and maps permit simplified dynamic
presentation of logistics, battle strategy, and personnel functions.

(5) Destruction of materiel can be shown by animation, thereby
making it unnecessary to. destroy actual equipment such as tanks,
barrage balloons, buildings, aircraft, and ships.

(6) Live-action photography often can be clarified by super-
imposing dimension lines or captions, or by a combination of anima-
tion and miniature models.

(7) Accurate miniature working models are constructed and
operated over miniature terrain in cases where natural locations
are not available. This technique has been successfullly used
in training films concerning large truck convoys and the destruction
of property by incendiary bombs.

(Applications of the various animation techniques listed above were illustrated by
the projection of a number of scenes produced at the U. S. Army Signal Corps Photo-
graphic Center.}

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Signal Corps Photographic Center, Astoria, Long Island, N. Y.

225

SOUND RECORDING AT THE SIGNAL CORPS
PHOTOGRAPHIC CENTER*

MAJOR GARLAND C. MISENER**

Sound-recording operations of the Signal Corps Photographic
Center are concerned principally with the production of army
training films and special service films. Sound is used in training
films very much the same as in commercial teaching films. De-
pending upon the type of subject and its treatment, some pictures
are photographed silent, then scored with narration and essential
effects; others are taken in live sound and augmented with effects
and library music in the re-recording process.

Narration and live sound are cut into the picture by editors in the
Editorial Branch. The picture is then turned over to the Sound
Branch for music and effects editing. Commercial effects records
are used to a limited extent. In most cases, however, authentic sound
must be recorded, either wild or in synchronism, for in many cases
the track is employed to demonstrate the characteristic sounds of
weapons, control mechanisms, motor ailments, etc. The negatives
of effects recorded specifically for a picture are catalogued in the
effects library and stored for future use.

The Sound Branch embraces the following activities : field record-
ing; recording of studio productions and narration score, domestic
and foreign; music and effects editing; re-recording, domestic
and foreign versions; installation and servicing of all sound-recording
and projection equipment; practical instruction of combat unit
personnel in sound recording.

The staff comprises both military and civilian personnel, including
many experienced studio and newsreel men. However, due to the
shortage of certain specialists, it has been necessary to make replace-
ments and additions to our staff by selecting and training other men
and women showing aptitude for sound production and equipment
maintenance. The field recording units usually comprise one officer

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Signal Corps Photographic Center, Astoria, Long Island, N. Y.

226

SOUND RECORDING 227

and three or four enlisted men. In the studio, the production day is
divided into two eight-hour shifts, in order to realize the most efficient
use of facilities.

EQUIPMENT

From a single sound and camera field unit of prewar days, the or-
ganization has undergone a manifold expansion, with a commensurate
broadening of studio and field recording facilities. Field recording
with portable channels was well under way at the time the base of
operations was moved from Fort Monmouth to the Astoria studios in
the spring of 1942. When the studios were occupied, two fixed chan-
nels of the original Paramount Western Electric installations were
taken over, along with two film machines and one disk recorder. In
addition, a new RCA re-recording channel was moved from Fort
Monmouth.

The portable recording equipment consists of a group of RCA
channels, purchased new and used as available. The older equipment
includes two PM-33 systems, one recording duplex track and the
other modified to Class A-B push-pull variable area.1 The film
machines of the newer channels record Class B push-pull. The choice
of Class B for original recording was based, first, upon a desire to
eliminate ground-noise reduction equipment, with its heavy drain
on the B supply, its relatively complicated adjustments and main-
tenance, and the unfavorable effects of its exposure control upon
sound reproduction due to peak-clipping and ground-noise modula-
tion. Moreover, the extended volume range of Class B not only
accommodates more adequately original sound of great volume
range, such as gunfire with its attendant breach and trajectory
sounds, but it permits also recording at lower modulation levels
speech and other sound in which overshooting produces objection-
able distortion. The latter consideration is especially important
when the recording channel does not include a compressor or volume
limiter, as is the case with our present portable equipment.

One of the Class B channels, less the remote pick-up equipment,
is shown in Fig. 1. The voltage and power amplifiers are mounted
on an iron framework in a Fiberbilt case, with the carrying handles
attached to the metal frame. Cable connections to this case, as
well as to all other components of the channel, are made through
Cannon P-type, six-pin connectors. Other fiber cases mount the
recorder and carry the magazines, B batteries, and accessories. To

228 MAJ. G. C. MISENER [j. s. M. P. E.

provide easier riding and to reduce vibration, Lord mountings have
recently been installed on the recorder and amplifier cases. The
recorder doors are being modified to incorporate red glass viewing
windows, in order that the recordist may check by observation the
film motion during takes.

Small, two-position mixers, which can be placed in any convenient
location, are used in the field. The mixer panel includes a high-speed
meter volume-indicator, a head-phone jack for the MI -3456 high-

FIG. 1. Portable recording channel, with converter control panel.

fidelity head-set, a pair of dial lights and a preamplifier heater supply
voltmeter and control. The volume indicator line is strapped to
the recording bus, and the monitoring head-set is fed through a trans-
former bridging the "VI" line. The recordist monitors the same
bus with crystal head-phones which plug into the recorder base. For
intercommunication between the mixer and recordist, Signal Corps
common battery field telephones are employed. The channel set-up
is indicated in Fig. 2. Western Electric 618-A and 630-A micro-
phones, the latter with baffles, are used in the field, while RCA MI-
3043-A unidirectional microphones are generally used on studio pro-

Sept., 1943]

SOUND RECORDING

229

ductions. Because of its light weight, the 630-A is chosen for field
work with duralumin fishpole booms. The feedback circuit of the
microphone amplifier is adjusted for normal high-frequency film-loss
equalization. The mixer circuit consists of two 250-ohm Daven
volume controls paralleled through a fixed matching pad.

The main amplifier case mounts an MI -102 13 voltage amplifier,
a low-pass filter, and an MI-3233-C bridging power amplifier. Ad-
justable dialog equalization has been provided in the form of variable
resistance in parallel with an added interstage coupling capacitor
in the power amplifier. A series of fixed resistors on the various
positions of a rotary gang switch comprise the variable resistance,
with the switch limited to screwdriver operation. The low-pass
filter consists of a constant-^ section and a shunt w-derived section
in cascade, shunt- terminated and unbalanced, using air-core coils

MICROPHONE

MIXER LL )

VOLTAGE

LOW PASS

^Snin

RECC

ROER

AMPLIFIER
MI-10209

^ -M

AMPLIFIER
MI-I02I3

FILTER
7000 CW

AMPLIFIER ]
M.-3233B | |

CL(

3301

r- i£J L

I2AWOV

MI-10209

• VOLT

l«0 AH
BATTERY

J
"I

6 VOLT
BATTERY

1
I

160 VOLTS U
BATTERIES |

12V

FIG. 2. Block schematic of portable channel.

wound in the sound shop. The case and transmission grounds are
isolated up to the input of the power amplifier. This ground system,
plus the radio frequency choke in the cathode circuit of the first
stage of the preamplifier, minimizes radio and radar pick-up.

Plate and heater supply is brought to the main amplifier case
through a single six-conductor cable, and is distributed to the pre-
amplifiers through the low-level cable to the mixer. The portable
channels operate on a standard cable-connection and impedance-
matching arrangement which permits corresponding components,
including recorders, to be readily interchanged. While the channels
are ordinarily kept intact, this interchangeability is of prime im-
portance in coping with emergencies and special situations.

The recorder is a PR-22 type, with ultraviolet optical system, and
is provided with interchangeable earner a- type motors. The 220-
volt synchronous motor is used on studio productions and in the
field with battery-driven converters. Some units in the field use
the d-c — a-c interlock system. The interlock motors are supplied

230 MAJ. G. C. MISENER [j. s. M. P. E.

by a 120- volt bank of airplane batteries through a control panel at
the recordist's position. The control panel mounts three motor-
cable receptacles, individual field controls for each motor and a 48-
cps Frahm frequency meter connected to the rotor circuit for monitor-
ing the motor speed. The individual field controls permit com-
pensation for differing motor loads, thus reducing any tendency to
hunt.

Field units carry tungar battery chargers, and ordinarily have
access to 110- volt a-c supply for charging batteries overnight. How-
ever, when companies work on locations remote from a-c supply, a
standard Signal Corps gasoline-powered motor-generator set is
carried for battery charging. The common 6- volt, 160-ampere-hour
automotive type storage battery is being standardized for low- voltage
supply. A Signal Corps extra-heavy-duty B Battery is employed for
B supply in the field. For use with the portable channels in the
studio, regulated B supplies have been constructed, employing stand-
ard cable connectors.

When using a portable channel on studio production, the recorder
and main amplifier case are either set up on a double-deck dolly in a
room just off the stage, or placed upon a bench in one of the base-
ment film-machine rooms. For the latter arrangement, wall re-
ceptacles are provided for operating over the permanent CTA lines
to the stages, and for d-c supply from rectifiers. Also available for
studio use is one RCA MI-3130-A mobile stage console or "tea
wagon," with a four-position mixer and adjustable dialog equaliza-
tion.

The azimuth adjustments of the push-pull recorders, as well as the
sensitometric conditions, are checked as regularly as possible by
recording cross-over2 and cross-modulation tests. Sound editing
of the push-pull track is accomplished with the aid of moviolas
modified for push-pull pick-up. This modification involves the
mounting of a beam-splitter such as that used at Republic Studios.
It consists simply of two small prisms mounted side by side im-
mediately below the sound-track scanning point, deflecting the light
transmitted by the two halves of the track directly onto the cathodes
of a type 920 photocell. Azimuth adjusting screws have been added
to the slit assembly to facilitate making the initial setting. The
adjusting screws may be removed after the setting has been tied off
with the clamping screws.

One Western Electric studio channel is used almost exclusively

Sept., 1943]

SOUND RECORDING

231

for narration scoring, domestic and foreign, while the second is used
on stage productions and scoring. The light-valves are biplanar,
clamped-bridge type, worked with 0.5 mil ribbon spacing and white-
light recording. The noise-reduction units have been modified for
high-speed operation. Mobile stage consoles, built by Audio Pro-
ductions, are used with the WE channels.3 These consoles include
an adjustable dialog equalizer and an RA-150 mixer amplifier.
Through CTA lines, the RA-150 feeds the bridging bus at the main

FIG. 3.

Variable-density film machine with associated control panels
and intercommunication devices.

amplifier rack. D -86 840 bridging amplifiers drive the valve and the
203-B volume indicator, and supply the monitoring system with direct
bridging bus monitor. Photoelectric-cell monitoring also is pro-
vided, with both monitors fed selectively into a B-42-A power
amplifier which, in turn, feeds a 200- A horn distribution panel.
Each position on the 200-A panel appears on a monitor-horn patch
bay.

A Lansing Iconic two-way speaker system is employed in the
monitoring room off the scoring stage, and 10-inch dynamic monitor-
ing speakers are mounted on baffles at the film machine positions.
Changing from direct to photoelectric-cell monitor is effected by

232

MAJ. G. C. MISENER

U. S. M. P. E

merely throwing a switch at the mixing console. The recordist is
able to alternate between direct and PEC monitor at the film machine
monitoring speaker, independently, by a simple change in patching
on a rack near the machine. One of the recorder positions is shown
in Fig. 3.

Intermodulation tests4 are recorded occasionally as a guide for
determining and maintaining optimal sensitometric conditions, and
the results are checked with listening tests on voice takes.

Foreign-version lip synchronous scoring is accomplished with the
projection of loops of composite domestic prints for cuing. Port-

FIG. 4. Block schematic of No. 1 recording channel.

able loop stands accommodating any loop up to 80 feet are used.
With the two projectors provided with loop stands, direct change-
overs may be made, which makes it possible for the recording schedule
to proceed without delays for threading. A third stand is available
for use on loops exceeding 80 feet in length.

The Western Electric machines and associated cameras, as well as
the machines of the re-recording channel, are operated from Western
Electric interlock distributors, of which there are four. These
distributors are powered by d-c drivers which are regulated by
700-A control panels. The four WE distributors, plus two smaller
RCA distributors with synchronous drivers, appear on a central
motor patch panel. The remote starting positions also appear on
this panel permitting the control of any distributor to be patched to

Sept., 1943]

SOUND RECORDING

233

FIG. 5(o). MI-9066-A re-recorders.

FIG. 5(&). Modified MI-9003-A Fantasound re-recorders.

234 MAJ. G. C. MISENER [j. s. M. P. E.

any film machine, projection, or camera position. The RCA relay
control boxes were modified by the addition of two relays, so that they
also operate from the WE remote control positions, making all six
distributors fully interchangeable in their application.

Mole Richardson type 103-B microphone booms and per-
ambulators are used on stage productions. Rubber suspension
hangers are provided for all types of microphones, and tinsel adapter
jumpers are used between the microphone and the cloth-covered

FIG. 6. Re-recording monitor room

boom cable.3 Adapters have been made to accommodate the 630
microphone in the hanger for the 618; this permits the use of either
microphone with a spherical windscreen which fits into the 618
hanger. The booms are equipped also with gunning devices.

The re-recording channel layout is shown in Fig. 4. The four
MI-9066-A re-recorders are theater- type heads, while the other four
re-recorders are modified Fantasound heads, fitted with standard
sound-head optical barrels, and using one of the four Fantasound
push-pull beam-splitter assemblies.5 The eight re-recorders shown
in Figs. 5 (a) and 5(6), as well as the main amplifier racks and the
PR-23 recorder, are installed in a basement room. The re-recorders

Sept., 1943] SOUND RECORDING 235

feed two-stage PEC amplifiers, which are essentially modified port-
able microphone amplifiers, over 250-ohm lines. These amplifiers
have approximately 45-db gain, as well as film-loss equalization;
they are mounted interchangeably in slides on platforms at the rear
of one of the equipment racks. To facilitate cross-patching, the
sound-head outputs, as well as the PEC amplifier inputs and out-
puts and the trunks to the re-recording console, all appear on a
patch bay.

The re-recording console and auxiliary film editors' tables were
styled by Mr. R. Holley of RCA to meet certain requirements of
this installation. The re-recording console, in relation to its position
in the monitoring theater, is shown in Fig. 6. The face of the con-
trol board is illuminated by a rectangular spot projected from a spot
mounted on the ceiling. At the base of the screen is a cabinet con-
taining a model 301 volume-indicator and a footage counter, both
of which are imaged on a translucent screen by rear projection. The
counter is relay-operated, with switching accomplished by a com-
mutator attached to the dubbing projector. A switch on the console
operates the footage counter reset solenoid.

Fig. 7 (a) shows the equipment layout on the mixing board of the
console. There are two 4-position MI-3108-A re-recording mixers
with a re-recorder trunk normaled to each input transformer. Nor-
maled between the input transformers and the control pads of the No.
1 or left-hand mixer are MI-10101 re-recording compensators and
type 85- Bl one-stage booster amplifiers. These compensation units
may be patched into any position of the No. 2 mixer as well. The
output of each mixer is amplified with a type 85-B1 booster amplifier,
and the booster outputs are combined in a mixing transformer which
feeds the return trunk to the main amplifier rack. Appearing on the
console patch bay is a compression section input and output; this
section includes an 80-cps high-pass filter and an MI-10206-A com-
pression amplifier mounted on the main amplifier racks, as well as
a ceiling control at the console. This section is operated as a zero-
gain device, and may be patched into the output of either 4-
position mixer. Thus, the mixer is provided with considerable
flexibility in the selective use of compression and compensation on the
various tracks handled.

An MI-3118-A utility attenuator panel, a UTC Model 4-B effects
filter, and two double-pole double-throw utility keys are mounted
on the mixing board and appear on the patch bay. The volume-

236

MAJ. G. C. MISENER

[J. S. M. P. E.

FIG. 7(a). Re-recording console mixing panels.

FIG. 7(6). Re-recording console patch bay.

Sept., 1943] SOUND RECORDING 237

indicator range switch, a talk-back intercommunication set, a signal-
light switch, and a monitor volume-control also are mounted on the
center panel of the console. At the top of the console, under the
hood, is an MI-3176 neon volume indicator,6 which may be used at
the mixer's discretion.

In order to make the patch bay readily available to the mixer, and
at the same time keep it out of sight and protected from dirt, it is
recessed under a door at the top right side, as shown in Fig. 7(b).
Illumination for patching is automatically switched on when the
patch bay door is opened. The jack strips are mounted on a metal
door which swings up on a hinge, affording convenient access to the
jacks for servicing. All the 85-B1 amplifiers are mounted on a hinged
rack inside the console in such manner as to afford convenient access
to the terminal strips and tubes. An intradepartmental PAX tele-
phone set and a telephone company set also are installed in con-
venient locations on the console.

The console output trunk is normaled to an Ml-10213 voltage
amplifier on the main amplifier rack. This voltage amplifier is to
be replaced by a second compression amplifier for volume limiting.
Following the gain amplifier are a 45-cps high-pass filter and an MI-
3121-C adjustable low-pass filter feeding the 500-ohm bridging bus.
An MI-3233-B bridging amplifier drives the galvanometer, while an
MI-3218-E ground-noise reduction amplifier, with logarithmic char-
acteristic, actuates the ground-noise reduction shutters. An MI-
3 110- A monitoring decompensator also bridges the bus and feeds,
through a monitor volume control on the console, the Western Electric
sound system in the re-recording monitoring room. By turning a
switch in the projection booth, the two TA-7400 projector sound-
heads appear on the patch bay of the console, which permits dubbing
sound from composite prints.

A second re-recording channel is being installed in order to cope
with the heavy production schedule.

Single-system sound cameras are used on newsreel type of coverage
for special service films. The equipment consists of Wall cameras
and RCA PM-43 sound systems, recording Class B push-pull with
ultraviolet exposure. A small 24-volt storage-battery unit provides
the A supply and camera motor power. One man can carry the
battery, amplifier, and accessory cases.

Greatly appreciated is the splendid cooperation given this or-
ganization by the equipment manufacturers in the installation and

238 MAJ. G. C. MISENER

servicing of the sound equipment. The excellent work of the military
and civilian personnel of the South Branch is also cited.

REFERENCES

1 CARTWRIGHT, C. H., AND THOMPSON, W. S.: 'The Class A-B Push-Pull
Recording System," /. Soc, Mot.' Pict. Eng., XXXIII (Sept., 1939), p. 289.

BLOOMBERG, D. J., AND LooTENS, C. L. : "Class B Push-Pull Recording for
Original Negatives," J. Soc. Mot. Pict. Eng., XXXIII (Sept., 1939), p. 664.

* STROCK, R. O.: "Some Practical Accessories for Motion Picture Recording,"
/. Soc. Mot. Pict. Eng.t XXXII (Feb., 1939), p. 188.

* FRAYNE, J. G., AND SCOVILLE, R. R. : "Analysis and Measurement of Dis-
tortion in Variable-Density Recording," /. Soc. Mot. Pict. Eng., XXXII (June,
1939), p. 648.

6 GARITY, WM. E., AND HAWKINS, J. N. A.: "Fantasound," /. Soc. Mot. Pict.
Eng., XXXVII (Aug., 1941), p. 127.

6 READ, S., JR.: "A Neon Type Volume Indicator," /. Soc. Mot. Pict. Eng.t
XXXVHI (June, 1937), p. 633.

FIELD CAMERA PROBLEMS*
CAPT. R. L. RAMSEY

At the outset of the war our photographic facilities and equipment
were called upon to fulfill the requirements of an all-out effort. It
was necessary to get good effective training films into the training
camps as soon as possible and it has only been through the steady
and untiring efforts of all concerned that we have, in a relatively short
time, been able to build up staff and equipment into a large working
unit capable of turning out training films in quantity and of
high quality. During the past year many problems have been en-
countered and investigated relative to the use of camera equipment
for photographic training pictures.

While there is considerable research and preliminary work and
thought required before a training film can be started, it is difficult
to anticipate every demand that will be made upon the cameramen
in the field. Many times it is necessary for cameramen to use their
ingenuity in the field to obtain and record the desired scene action.
It is not always easy, as the resources that are made available to regu-
lar studio workers are not at hand.

In many instances the type of work being shot is of such nature
that it must be taken on a catch-as-catch-can basis, similar to news-
reel work. Another important consideration that confronts photog-
raphers of training films is, "Does it Teach ?" Unlike regular photog-
raphy it is sometimes necessary to sacrifice pictorial quality for the
purpose of emphasizing a training point. It is, however, necessary
that the picture composition at all times be both pleasing and natural,
while at the same time it is instructional. In this connection it has
been necessary for many experienced cameramen coming into the
Signal Corps Photographic Center to adopt new and revised methods
of photographing scenes and to find ways of overcoming the obstacles
that present themselves in the field.

As an example of such difficulties, Fig. 1 shows the conventional

* Presented at the 1943 Spring Meeting at New York, N. Y,
** U. S. Signal Corps Photographic Center, Astoria, Long Island, N. Y.

239

240

CAPT. R. L. RAMSEY

[J. S. M. P. E.

FIG. 1. Outdoor overhead parallel platform.

FIG. 2. Close-up of Fig. 1.

Sept., 1943] FIELD CAMERA PROBLEMS

241

FIG. 3. A crude but practicable impromptu boom.

FIG. 4. Shooting under difficulties.

242

CAPT. R. L. RAMSEY

[J. S. M. P. E.

type of overhead parallel platform used in filming one of our recent
training films. While this equipment is similar to what would be
used in a regular commercial studio it shows that shooting training
films in the field is not a one-man job. Many times it is necessary
to have two or three cameras working on the same shot. Fig. 2
is a close-up of the same parallel assembly, showing the kind of set-
up and camera equipment used. As can be seen, this is regular
studio equipment.

FIG. 5. Shooting from a fox-hole.

Fig. 3 illustrates the ingenuity of some of the men. It was neces-
sary to make a boom shot out in the field, and this crude but practical
boom was constructed out of the available materials. While it was
indeed crude, it did the job, which was the all-important thing since
the work we do is measured against the time consumed.

Fig. 4 shows another kind of shot we are sometimes called upon to
make. It illustrates a rather cramped shooting position for full-size
camera equipment. In most instances there is not sufficient time
or facilities for doing such photography inside the sudio, where
special lighting and equipment can be used. Here again, the camera-

Sept., 1943]

FIELD CAMERA PROBLEMS

243

man must use his ingenuity and take advantage of the available equip-
ment to obtain the desired effect.

Fig. 5 shows an Eyemo Camera being used in a fox-hole with army
trucks running overhead, and illustrates again the variety of equip-

FIG. 6. Trailer and jeep.

ment necessary for filming training pictures. It is often necessary
to assemble equipment for short-order jobs, and locations for shooting
are usually in remote parts of the country. For such assignments
it is necessary to supply the crew with equipment suitable for any

FIG. 7. The contents of the trailer.

sort of photography they may encounter. With the benefit of past
experience and a knowledge of the various difficulties encountered,
we set forth to assemble an experimental mobile camera unit. The
considerations confronting us are that the assembly of equip-

244

CAPT. R. L. RAMSEY

[J. S. M. p. E

FIG. 8. Cameras in position.

FIG. 9. Mounting of the Mitchell, and the hydraulic pedestal.

Sept., 1943] FIELD CAMERA PROBLEMS 245

ment should be compact, light in weight, readily mobile, and suit-
able for all kinds of photography.

Fig. 6 shows the trailer attached to the jeep which is used for con-
veying the entire outfit. We are all aware of the versatility of the
jeep, and in designing the trailer we endeavored to make it just as
practical. The trailer is equipped with electric hydraulic brakes
and is completely protected against weather. It measures ap-
proximately 5 X 6 X 6 ft, and weighs 2700 pounds whem com-
pletely loaded.

Fig. 7 shows the contents of the trailer. A standard Mitchell
camera is provided which can be mounted on a hydraulic pedestal,
which is a permanent part of the jeep. The camera can be raised
or lowered as necessary, and the usual gyro head serves all the pur-
poses of a rigid mounting for stationary and mobile work. Tripods
of various sizes are also provided for mounting the camera when it
is to be used in the field. A 400-ft spider Eyemo is available, as
is also a 100-ft model when it is necessary that hand-held shots be
made. A 4 X 5 Speed Graphic still camera and complete accessories
are also provided. Two broad-light units and one spotlight are
included. The lighting equipment can be operated on regular electric
supply lines, when available. A field-developing kit, reflectors,
additional magazines, and all the other expendables required are also
included.

Fig. 8 shows the outfit with two cameras mounted for photo-
graphing. The top of the trailer is flat, so we have the equivalent
of an upright platform.

Fig. 9 shows the mounting of the Mitchell Camera and the hy-
draulic pedestal. This pedestal is an integral part of the jeep, rigidly
mounted and reinforced for stationary or travelling shots. It is
raised or lowered by the means of a foot-pedal at the base. An
extension to the pedestal is provided it the camera needs to be raised
beyond the limits of the hydraulic lift.

The illustrations may convey some idea of the kind of work being
done. The jeep and trailer combination is purely an experimental
assembly, but already many uses have been found for it.

MULTIPLE-FILM SCENE SELECTOR*
CAPT. HARRY W. LEASIM**

The Western Union Engineering Laboratories have just completed
installation of five multiple-film scene selectors in The Pentagon,
Washington, D. C. These units are used by the Army Pictorial
Service in conjunction with the editing of motion picture films.

Prior to the installation of the mechanism, it was the custom to
show the film to one person at a time. This person would actuate a
buzzer whenever he saw a portion of the projected film he wished to
have reprinted for his purpose. The operator in the projection
room inserted a piece of paper into the take-up reel, and the process
was called "papering" the film. Many hours were expended in this
individual viewing of the same film as many representatives of various
branches of the Army had to see the film to determine what parts,
if any, would be reacquired by their respective organizations.

The director of Army Pictorial Service assigned qualified officers
to find a solution of this problem. Knowing of several types of
devices in satisfactory use by the Western Union Telegraph Company,
a meeting was arranged with Mr. Dudley, Chief Engineer of the
Western Union Company, and his assistant, Mr. Dirkes. The
problem was discussed with them and several types of equipment
were inspected with the point of view that any equipment that would
require designing and retooling in manufacturing would not be desir-
able in view of the urgency of procuring the device. The Western
Union Reperforators 10 A were found to be satisfactory for the basic
purpose.

Each perforated tape is capable of bearing five intelligence holes
and one feed-hole, perforated transversely to the length of the tape
at each tenth of an inch of tape. The reperforators are so arranged
that each horizontal row of holes is associated with an editor so that
on each perforated tape the requests of five editors will be recorded.

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Pictorial Service, Washington, D. C.; deceased, June 24, 1943..
while on duty in California.
246

MULTIPLE-FILM SCENE SELECTOR

247

The selection of film is made by the elimination of the associated
horizontal row of perforated holes from the tape when the part of the
film desired is being ordered.

The mechanism is arranged so that with the progression of one foot
of film through the projector one transverse row of five holes will be
perforated in the tape.

FIG. 1. Lead table (left) and auxiliary table (right).

The unit consists of a so-called lead table and a number of auxiliary
tables, each of which records the requests of five editors. In the
installation recently made, one of the sets consists of a lead table and
three auxiliary tables, permitting twenty editors to register their
requests. Four auxiliary tables can be added, and the number of
editors increased to forty.

Each editor is provided with a switch and light unit at his writing
desk position. As he watches the picture, he makes a request for

248

CAPT. H. W. LEASIM

[J. S. M. P. E.

part of film by rocking a Levolier switch in the unit. A red lamp,
also a part of the unit, glows, indicating that the request is being
registered. When no more film is desired, the editor again rocks
the switch and the light is put out, indicating that the request is
ended. The mechanism is capable of registering requests for both
35 and 16-mm film.

The prepared tape, when ready for the cutting room, is run through
a multiple film scene selector tape meter (Reader). The tape meter

FIG. 2. Close-up of reperforator 10 A .

counter is set to zero, and the tape is placed under the latch at the
starting point. It is speedily fed through a tape transmitter until
a request is encountered, whereupon one of a series of lamps is lighted,
indicating in which row of holes a request is recorded and stopping
the tape so that the operator may note the point in the film at which
the request was made. The switch associated with the lamp is then
thrown and the machine progresses until such time as another re-
quest is made or the initial request is ended, whereupon another lamp
is lighted and another reading made.

Sept., 1943] MULTIPLE-FILM SCENE SELECTOR

249

FIG. 3. Impulse unit 3A.

FIG. 4. Lead table and three auxiliary tables in the Pentagon Build-
ing installation.

250

CAPT. H. W. LEASIM

Fig. 1. shows a lead table (left) and auxiliary table (right). The
covers have been raised to show the mechanism. Fig. 2 is a close-
up of Reperforator 10 A and Fig. 3, the impulse unit 3A. Fig. 4
shows one lead table and three auxiliary tables installed in the
auditorium in The Pentagon Building. Fig. 5 shows the tape
meter.

FIG. 5. Tape meter.

The installation is now operating very satisfactorily. The mul-
tiple-film scene selector allows twenty representatives to review
the film at the same time and provides for them access to the initial
showing and selection of film so that the interested Services will have
copies of films they desire without any loss of time.

FILM DISTRIBUTION*

LT. JAMES D. FINN**

It is certainly calling attention to the obvious to state that all the
effort in planning and producing training films would be wasted
without an efficient system of distribution that would put the films at
the right places and at the right times for effective use. With millions
of men in our Army scattered all over the continental United States
and in many foreign theaters, efficient film distribution assumes the
proportions of a tremendous problem in administration and supply.

After months of work, a new system of decentralized training
film distribution has been worked out. It is the purpose of this
paper to describe the functioning of the distribution of all United
States Army films under this new decentralized system.

Since training films, • film-strips, film bulletins, and information
films are not produced for theatrical entertainment, they can not
be distributed on the same basis as theatrical films. Army films
must be available at all times for showing to the men at any phase
in the training period. The vital message of the films — a message
that may mean the difference between life and death on the battle-
field— must not be left to chance. Accordingly, it has been necessary
to set up libraries of films and film-strips at all centers where troops
are in training. These libraries act as the supply agencies.

For the administration and housekeeping purposes of the Army,
there are nine Service Commands in the United States. The Com-
manding General of each of these Service Commands is responsible
for all housekeeping and administration of the posts, camps, and
stations within the several States comprising his command.

The basic unit of the Army film distribution system is the Central
Distribution Library in the Headquarters of each Service Command.
These Central Libraries have two distinct functions. One function
is to supply films on loan to installations in the Service Command

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Pictorial Service, Washington, D. C.

251

252 LT. J. D. FINN [j. s. M. p. E.

that are not large enough to have libraries. These installations in-
clude ROTC Departments, Ordnance bases, depots, and other small
and isolated establishments. The second function of the Central
Distribution Library is to act as a supply point for the various
libraries at posts and camps.

The libraries at posts, camps, and stations within a Service Com-
mand are called sub-libraries. These libraries are divided into four
classes, based upon the soldier population they serve. This classi-
fication of libraries A, B, C, and D exists mainly to control the
amount of projection and library equipment issued.

Requests for additional prints of films for permanent retention
are forwarded from the sub-libraries to the Central Distribution
Library, and the orders are filled from stock. On initial distribution
of new films, the Central Library makes recommendations to the
Army Pictorial Service, and the prints are supplied direct in accord-
ance with these recommendations. Sub-libraries may obtain prints
on loan from the Central Libraries at any time, and, if the need arises,
they may order prints for permanent retention.

In order to keep the Service Commands informed so that initial
distribution recommendations may be made* and acted upon without
delay, the Army Pictorial Service furnishes information on the scope
of the film and on the distribution recommended by the approving
agencies.

This system has been evolved so that the right subjects get to the
right places and little raw stock is wasted. The Service Command,
for example, knows that the 1000th Cavalry is mechanized and has
no use for such a title as the Horse Gas Mask, whereas if prints were
distributed directly from Washington without these recommendations
it might be possible that the Horse Gas Mask would end up on the
shelf of a library serving tank units.

Some of the libraries within a Service Command are small and
specialized and do not need to be included in any initial distribution.
These libraries are called Auxiliary Libraries and are serviced from
the Central Library or nearest sub-library. Only occasionally are
prints required for permanent retention by these libraries. The
designation of auxiliary libraries also prevents stock from being
wasted and films from resting for months on library shelves.

The basic system of film distribution for Army training films then
revolves around the library system. The nine Central Libraries,
the sub-libraries, and auxiliary libraries stemming from them form a

Sept., 1943] FILM DISTRIBUTION 253

distribution network that reaches out and touches the training of
every soldier in the Army.

The American soldier, however, these days is wandering far from
his native shores; and wherever large concentrations of men go,
the film distribution system must follow them. Training takes
place at overseas bases, and modern training requires films. Hence,
a large number of overseas libraries have been created and are served
directly by the Army Pictorial Service upon recommendation of the
various Theater Commanders.

Another function of the distribution program involves the use of
films not made by the Army. Films made by the British Govern-
ment, for example, are sometimes adapted for use as U. S. Army
training films and are distributed as such, but many others are made
available to special Army installations on loan from the Army
Pictorial Service. Films made by the United States Office of Educa-
tion for the training of industrial workers have been converted
where applicable and are distributed as training films.

Films made for the Special Service Division for orientation of the
American soldier, such as the Why We Fight series, and films made
for the Industrial Relations Division of the War Department Bureau
of Public Relations for factory worker morale, are also distributed
on a special basis. This latter type of distribution is operated on the
familiar principles of theater booking.

Training-film distribution to Army Air Forces installations is not
within the jurisdiction of the Army Pictorial Service. The Air
Forces operate their own distribution system.

So far this paper has described the functioning of the general
organization for the distribution of Army films. A great deal
of detail work is involved which does not appear in this general
description. For example, it was necessary to develop a booking
system for the Central Distribution Libraries, and for the various
sub-libraries, that would make the right film available at the right
time for the using unit, and at the same time give enough informa-
tion to make it possible to apply an inventory control.

This booking system is a combination system incorporating the
best theatrical and non- theatrical practices, and certain new devices
made necessary by the peculiarities of military organization.

Inventory control has been established in order to prevent use of
unnecessary raw stock. Film stocks are checked by the Service
Corrmands and reports are rendered monthly to the Army Pictorial

254 LT. J. D. FINN

Service. By comparing stocks against booking and needs, it is
possible for the Service Commands to re-allocate existing stocks and
cut down the making of new prints.

TABLE I

Eighth Service Command — Extract of Report on Attendance

December, January, February,

1942 1943 1943

Total number of bookings (all libraries) 13,396 14,886 20,159

Total number of screenings 19,993 25,819 26,919

Total attendance 2,284,997 3,550,853 3,745,465

Total number of previews held 136 315 341

Attendance at previews 3,959 6,944 4,507

The library reports serve also as a rough check on use, indicating
by the number of showings and previews the extent to which avail-
able films are being used. Table I shows a tabulation of a portion of
the report from the Eighth Service Command for a period of three
months. It is obvious from a study of the total attendance figures
that film use grows even over a short period of time. When we know
that in the month of February, 1943, the attendance at film showings
in the Eighth Service Command alone was 3,745,465, and that the
message delivered at those showings will help toward success in
battle, then we know that in a new way we are "Getting the Message
Through."

FILM UTILIZATION*

BOYD T. WOLFF**

The utilization of films in the military training of our Army must
be considered in the light of the tremendous job they have to do.
Our films have to teach an Army to win a world ; our films are for a
student body of two million, five million, seven million, and more
soldiers; our films are for a military training program in the greatest
educational job we have ever undertaken — the establishment of a
University of the American Army. Here is visual education on a
scale that staggers the imagination of the most ardent instructional
film enthusiast of prewar days.

This job calls for something different, something the makers of
films have never done, something the users of films have never seen.
It calls for a coordinated program of films complete from production
to utilization. The training film program of our Army is, therefore,
something new in visual instruction.

It is new in size, with more than 1000 titles, in 250 film libraries,
for 7,000,000 men.

It is new in scope, with 25 different series, for every branch of the
Service from Air Corps to Transportation Corps; with four different
kinds of films (training films, film-strips, film bulletins, and informa-
tion films) for four different needs (motion, stop-action, news, and
history) ; and films adapted from United Nations pictures and from
captured enemy pictures.

Producers, writers, directors, cameramen, technicians, actors,
instructors, projection equipment experts are putting together their
various skills in one unified set-up. Four major aspects of visual
education — production, distribution, utilization, and evaluation — are
bound together into a single organization, the Army, to achieve a
common objective — training combat troops to be superior to the

* Presented at the 1943 Spring Meeting at New York, N. Y.
** U. S. Army Pictorial Service, Washington, D. C.

255

256 B. T. WOLFF [J. S. M. P. E.

enemy. The purpose of this paper is to show how the Army utilizes
films in military training, and what happens when the way films are
used is considered as important as the kind of films used. One of
the chief characteristics of Army films is that they are produced to
fit specific objectives and to match definite plans prescribing their
use in training.

Training Films are officially described as "sound motion pictures
produced specifically for use as aids in expediting and standardizing
instruction of the Army." Nearly all of them are available in both
16 and 35-mm size. "Each film follows the principles of accepted
teaching method, is designed for showing before a particular audience
group, and conforms in all details to approved War Department
doctrine or technique."

Film-Strips are "series of still transparencies portrayed on in-
dividual consecutive frames of a str/ip of 35-mm motion picture
film."

Film Bulletins "are designed to inform military personnel of current
activities and developments in the war effort. It is desired that
training officers employ these bulletins as an orientation medium and
aids to instruction whenever possible."

Information Films are being produced as a new series under the
general title, Why We Fight, to furnish military personnel with
historical and general background information on the war. All these
films are coming to reflect the global nature of the war as more and
more are made from converted United Nations pictures and from
films captured from the enemy.

Since these different types are produced not merely for variety's
sake, the kind of job that each can do best must be clearly under-
stood. Training films utilize to the fullest extent the element of
movement. In dealing with any subject, the Army makes the most
of showing possibilities ranging from minute workings of the smallest
part to general operations over a large field. The utmost use is
made of the camera's capacity to give a bird's-eye view or a micro-
scopic close-up. The training film story may race through time
or sweep over space, but always its prime purpose is showing people
and things, individuals and parts, plans and events, in action.

Film-strips are utilized where the element of stop-action is of
paramount importance. Where an arrangement of relationship
needs longer study without consideration of movement, as in learning
nomenclature, identification, construction, etc., these are held in

Sept., 1943] FILM UTILIZATION 257

view on the screen while the instructor comments as long as may be
necessary. In this way the speed of showing is adjusted to the
learning rate of the class.

Since basic technical principles of visual training and conditions for
projection are common to all film aids, however, the term "training
films" is used hereafter to mean any or all film aids except where
specifically differentiated.

As to content and subject matter, both training films and film-strips
are for specific training in military regulations, mechanics, techniques,
and tactics in accordance with approved military doctrine. These
comprise four groups arranged according to training plans to fit
successive stages and specialized aspects of the soldier's instruction.

First the basics, required showing to recruits at Reception Centers.
These pictures deal with first things first, take nothing for granted,
leave no room for guesswork, introduce the new soldier to the Army.
How must the enlisted man conduct himself? What is expected of
him ? He sees the film Military Courtesy and Customs of the Service.
What are the rules and regulations that will govern his life in the
Army? The A r tides of War answers this question. What should he
do if exposed to venereal disease? Sex Hygiene shows what to do and
where to do it. Such matters are dealt with plainly. The first
training films soon dispel any previous notions the recruit may have
as to the effectiveness of old-wives' remedies or quacks' nostrum
in dealing with the facts of life. Along with these he gets a glimpse
of the fundamentals of soldiering, in a group of films that every
enlisted man must see: Identification of Aircraft, Adjustment and
Inspection of Gas Masks, Map Reading, Anti- Mechanized Defense,
Use of Natural Cover and Concealment, Weapons, Drill, First Aid,
Safeguarding Military Information, etc.

Second, third, and fourth groups of training films and film-strips
are classed as mechanical, technical, and tactical, respectively. While
they are not necessarily programed in that order, these are the films
for advanced training of specialists. They are concerned with the
structure, assembly, and disassembly of our own secret weapons, and
the operation of vehicles.

The film bulletins cover experiments with, or trials and tests on,
materiel, or methods that have not been accepted as official doctrine.
They help the individual soldier see where his special function fits
into the vast Army organization as a whole.

The information films are full-length features to give a broad

258 B. T. WOLFF [J. S. M. P. E.

perspective of the war and the world in which it is being fought.
These films are not intended to train the soldier in special techniques
or knowledge, or to tell him directly how to do anything better; they
are intended to enlist his sympathies and full emotional strength for
fighting. They are to deepen and to extend his understanding of
our cause. They are shaped primarily to get a response from his
mind and heart rather than from his hands and body, to affect his
attitudes rather than aptitudes; but in so doing, ultimately to make
him a totally better fighting man. Information films produced so
far are Prelude to War, The Nazis Strike, Divide and Conquer, and
Battle of Britain. Pictures planned to round out the series are The
Battle of Russia, The Battle of China, and America in the War.

None of these films is conceived as a substitute for the other.
Each has the single message it can get across better than any of the
others. It may happen that a training film, a film-strip, a film
bulletin, and an information film may be on the same subject; but
each represents a different approach, a different emphasis or treat-
ment. For instance, on the subject of tanks, the training films
Armored Combat Vehicles, Armored Force Drill, Basic Tank Driving,
and Advanced Tank Driving deal with types of tanks and methods of
using them, explaining their potentialities and limitations — long
shots and close-ups in logical instructional sequence, with repetition
and summary of important points. The film-strips First Echelon
Tank Maintenance, Tank Track Maintenance for the Light M3 and the
Medium M3 and Tank Inspection cover common nomenclature,
dimensions, details of construction and function, and diagrams of
procedure, one step at a time. The film bulletins U. S. Army Medium
Tank M3, Tank Obstacles and Army Tank Destroyers demonstrate
trial methods of stopping tanks with obstacles, under severe test-
ing conditions. The information film The Nazis Strike shows the kind
of enemy tank action, in Czechoslovakia and Poland, that our troops
must learn to combat. The Army instructor extracts the full value
of each type of film aid by using it in planned relationship to the
others and to his whole lesson. He sees to it that the manner in
which the film treats the subject matches the way in which he in-
tends to treat the lesson. He fits the film to the sequence of activi-
ties in training plans.

All these films are tools of instruction. They are source ma-
terials for a method of training, requiring their own method of
specialized technique. They are vital weapons in the arsenal of

Sept., 1943] FILM UTILIZED 259

democracy. As such they demand just as much skill and under-
standing in then: use as any other material of modern, mechanized
warfare.

The first job of the Army instructor is to see that his men know
how to look at films. He has to begin by explaining the difference
between films "Produced by Military Authorities for Military Per-
sonnel for Military Objectives," and the kind of movies most of them
are used to going to for amusement. He must explain why films are
used in training and why there are different kinds of training films.
The men have to learn the difference between really studying a film
and merely watching it to see "How it comes out," for training films
have to take. They must stick. They can not afford to be "filed or
forgotten."

Among other things, the men have to learn how to observe a film
selectively, systematically, and with concentration; how to take
notes; how to ask significant questions. The instructor has to decide
from his knowledge both of his subject and his men how many
repeat showings are necessary and at which stages of the lesson they
are needed. This varies as films vary between "basic" and "highly
specialized technical" training films. It varies as men vary from
those barely able to read to those with college training.

Training films are not presented as a short-cut to learning, or as
necessarily easier than other methods. In no sense are training
films frills. They are not meant to glamorize training. Our Army
has a lot to learn in a little time, and training films teach more, in a
clearer, faster way than any other means of instruction. As the
largest group of potential learners in the world this unique film audi-
ence realizes it is there to learn the most serious lessons in the world.

To get this lesson across, the procedure for the most effective
utilization of training films corresponds to the general sequence of
steps outlined in the basic field manual on military training as
follows :

The first step is preparation. Each film must be previewed by the
instructor before showing. The instructor also must arrange in
advance for booking the film and for the equipment, projectionist,
and classroom. He must study correlative training literature.

The second step is explanation. Before each film showing the men
are given a brief account of what the film is about and what they are
expected to learn from it. They are informed that they will be
quizzed on its contents.

260 B. T. WOLFF [j. s. M. P. E.

The third is demonstration. This is the showing of the film itself.
The instructor is responsible for setting up good screening conditions.

Before the filming he makes sure that the right film is ready, that
the projector is set up and in working order, and that the screen is
placed within the proper sight lines, without posts or other obstruc-
tions in the line of vision. He must arrange for maximum com-
fort of the audience and see that the room is ventilated and darkened
to the extent of existent facilities; for it must be remembered that
few of the projection rooms were designed for screening purposes.

The fourth is application. As often as possible the film lesson is
applied in practice. It is recognized that vivid as a motion picture
may be, it is one step removed from reality. The men are taken
directly to such areas of activity as the drill field, the firing range, the
shop, the convoy, the patrol, so that they may make the visualized
experience their own through seeing, hearing, feeling, doing. Other
visual aids such as models, sand tables, wall displays, still photo-
graphs, diagrams, charts, maps, etc., related to the same subject
are used as supplementary materials for study by individuals and
small groups.

The fifth is discussion. Here also the men have a chance to
participate. They ask and answer questions. In this phase of the
instruction they show which things they learn quickly and which
slowly, where their greatest difficulties lie and how the instructor
can help them most.

The sixth and last step is examination. Following each screening
the instructor asks fifteen questions which he has previously written
on the film. A unique method has been worked out to simplify the
administration of this quiz.

Each soldier is provided with a training film quiz card in duplicate.
The card has two columns of fifteen tabs each — one column for
answering "yes" and one column for answering "no." As each of
the fifteen questions is asked, the student punches out the tab that
he thinks gives the correct answer. When the questioning is ended
he immediately hands to the instructor his duplicate card, with his
name on it, and keeps the original as a record of his progress through-
out the course. The instructor then reviews the quiz announcing
or writing on the blackboard the correct answers so that each man
will know his score before leaving the classroom.

The sequence of these steps may be varied to suit the circumstances
and it makes no essential difference whether the whole procedure is

Sept., 1943] FILM UTILIZATION 261

carried out during a single day or over a longer period of time. The
instructor must know what he is going to do all the way through
his cycle of instruction before he starts a course. He must take into
account all possibilities. He must aim to use the film in such a way
that without it something would be missing, and with it something
is added that no other medium of instruction can supply.

Since training plans and schedules provide a "place for every
film," every film must be used in its proper place — that is, only in
connection with definite training objectives. These objectives are
set by the highest training echelons which set up long-range schedules
called Mobilization Training Programs for their accomplishment.
Training programs that actually bring together soldiers, instructors,
equipment, time, and place are worked out by division, regiment,
and battalion training officers. Since all training films are designed
for use in a larger plan, their full utilization is realized only when
they are related to other coordinated activities of military training.

To expedite the use of training films in the field, the Film Distribu-
tion and Utilization Branch of the Army Pictorial Service provides
the following services and publications :

Visual Aid Coordinators: for each of the nine Service Commands
to give overall assistance on the spot where the films are actually used.
As consultants and trouble shooters they bring all possible help
from the War Department to assist in the installation of new film
libraries and in the most effective use of films in training. What they
find out in the field helps to bring about needed changes in pro-
cedure.

Basic Field Manual 21-7 gives a complete list of titles and brief
notes on all training films, film-strips, and film bulletins. It is
published twice a year.

- War Department Training Circulars, with current information on
Army Films, are printed monthly.

The Film Distribution and Utilziation News Letter is issued in
mimeographed form bimonthly with general reports on most recently
approved and distributed films, and new developments in film
utilization in the Service Commands and in the Army Pictorial
Service.

Training Film Outlines for each training film produced.

Research Bulletins announce results of surveys on film utilization.

Standarized Quiz Answer Cards.

262 B. T. WOLFF

In summary, it should be remembered that training films, film-
strips, film bulletins, and information films are an integral part of
the total military training program. They are not "extra added
attractions" of military training. The Army has gone all out for
visual training and it is bending every effort to see that the highest
degree of skill in their use is developed. Films as materiel of war
are one of the most potent of weapons in our arsenal of democracy.

It is hoped that the private industrialist who may be fearful that
the government is taking over all film stock may take comfort in the
fact that the way is being prepared for an educational film industry
in peacetime such as never before has been conceived. It is hoped
that the public, complaining perhaps of fewer new films at local
theaters, will remember that there are more new films being made to
help train our Army to save our lives.

FIFTY-FOURTH SEMI-ANNUAL TECHNICAL CONFERENCE

OF THE

SOCIETY OF MOTION PICTURE ENGINEERS

HOLLYWOOD-ROOSEVELT HOTEL, HOLLYWOOD, CALIF
OCTOBER 18-22, INCLUSIVE

Officers and Committees in Charge

HERBERT GRIFFIN, President

EMERY HUSE, Past-President and Chairman, Local Arrangements

LOREN L. RYDER, Executive Vice-P resident

W. C. KUNZMANN, Convention Vice-P resident

A. C. DOWNES, Editorial Vice-President

E. A. WILLIFORD, Secretary

C. W. HANDLEY, Chairman, Pacific Coast Section

JULIUS HABER, Chairman, Publicity Committee

Papers Committee

C. R. DAILY, Chairman
C. R. KEITH, Vice-Chairman East Coast

F. W. BOWDITCH

G. A. CHAMBERS
F. L. EICH

R. E. FARNHAM
J. L. FORREST

J. FRANK, JR.
J. G. FRAYNE
P. A. McGuiRE
E. W. KELLOGG
G. E. MATTHEWS

H. W. MOYSE

W. H. OFFENHAUSER

V. C. SHAUER

S. P. SOLOW

W. V. WOLFE

Reception and Local Arrangements

H. J. CHANON
J. G. FRAYNE

A. M. GUNDELFINGER

C. W. HANDLEY
E. H. HANSEN
J. K. HILLARD
E. M. HONAN

C. W. HANDLEY
E. HUSE

EMERY HUSE, Chairman
M. S. LESHING
W. C. MILLER

R. H. McCULLOUGH

P. MOLE
F. K. MORGAN
H. W. MOYSE
W. A. MUELLER

Registration and Information

W. C. KUNZMANN, Chairman

G. F. RACKETT

H. W. REMERSHIED

L. L. RYDER

C. R. SAWYER

S. P. SOLOW

J. R. WILKINSON

W. V. WOLFE

R. G. LlNDERMAN

H. SMITH, JR.

263

264 FIFTY-FOURTH SEMI- ANNUAL CONFERENCE [J. S. M. p. E.

Publicity Committee

G. R. GIROUX, Chairman

J. W. BOYLE JULIUS HABER

C. R. DAILY C. R. KEITH

G. GIBSON E. C. RICHARDSON

Luncheon and Dinner-Dance Committee

LOREN L. RYDER, Chairman

A.M. GUNDELFINGER P. MOLE R. R. SCOVILLE

H. T. KALMUS H. W. MOYSE S. P. SOLOW

E. M. HONAN W. A. MUELLER J. R. WILKINSON

E. HUSE H. W. REMERSHIED W. V. WOLFE

Hotel and Transportation

A. M. GUNDELFINGER, Chairman

A. C. BLANEY A. F. EDOUART O. F. NEU

L. W. CHASE H. GOLDFORB G. E. SAWYER

H. J. CHANON G. T. LORANCE N. L. SIMMONS

L. E. CLARKE W. C. MARCUS W. L. THAYER

Projection Committee

35-Mm Programs
R. H. McCuLLOUGH, Chairman
L. R. ABBOTT W. E. GEBHARDT, JR. C. R. SAWYER

B. FREERICKS W. W. LINDSAY, JR. W. V. WOLFE

C. R. RUSSELL
Officers and Members of I.A.T.S.E. Locals 150 and 165

16-Mm Programs

H. W. REMERSHIED, Chairman

A. H. BOLT A. M. GUNDELFINGER

C. DUNNING J. RUNK

Ladies Reception Committee

MRS. C. W. HANDLEY, Hostess

There will be o special or prearranged ladies entertainment program during
the five-day 1943 Fall Conference. However, a reception parlor will be available
in the Hotel where the ladies may meet daily. The ladies are cordially invited
to attend the functions of the Conference.

TENTATIVE PROGRAM

Monday, October 18th
9: 30 a.m. Hotel Lobby; Registration.
The program for the morning of this date will be announced later.

12:30 p.m. Terrace Room; Informal Get-Together Luncheon for members, their
guests, and families. The luncheon program will be announced later.

Sept., 1943]

FIFTY-FOURTH SEMI-ANNUAL CONFERENCE

265

2: 00 p.m. Blossom Room; General Session.

8: 00 p.m. General Session; the location will be announced later.

Tuesday, October 19th

10:00 a.m. Hotel Lobby; Registration. Open morning.
2: 00p.m. Blossom Room; General Session.
8: 00 p.m. General Session; the location will be announced later.

Wednesday, October 20th

9:30 a.m. Hotel Lobby; Registration.
10:00 a.m. Blossom Room; General Session.

2 :00 p.m. Open afternoon for recreational program to be announced later.
8: 00 p.m. Blossom Room; SMPE Fifty-Fourth Semi-Annual Dinner-Dance.
The program for the evening will be announced later. ( Dancing until
12:30 a.m.; strictly informal business dress and uniforms only.)

Thursday, October 21st

10:00 a.m. Open morning.
2 : 00 p.m. Blossom Room; General Session.
8: 00 p.m. General Session; the location will be announced later.

Friday, October 22nd

10:00 a.m. Blossom Room; General Session.
2: 00 p.m. Blossom Room; General Session.
8 : 00 p.m. Blossom Room; General Session and Adjournment.

Conference Headquarters

Room with bath, one person $3.85

Room, double bed, with bath, two persons 5.50

Room, twin beds with bath, two persons 6.60

Small suite, parlor, bedroom with bath, single or double occupancy 8.80

Indoor and outdoor parking facilities will be available at the Hotel head-
quarters if desired.

266 FIFTY-FOURTH SEMI-ANNUAL CONFERENCE [J. S. M. p. E.

The Conference registration headquarters will be located in the Hotel Lobby,
and members and guests will be expected to register and receive their badges
and identification cards. The registration fees are used to help defray the
Conference expenses, and cooperation in this respect will be greatly appreciated
by the Local Arrangements Committee.

Note. — The 1943 Fall Technical Conference is subject to cancellation if later
deemed advisable in the national interest.

W. C. KUNZMANN
Convention Vice-President

PAPERS PROGRAM OF THE FIFTY-FOURTH SEMI-ANNUAL
TECHNICAL CONFERENCE

The Papers Program for the Fifty-Fourth Semi- Annual Technical Conference
is progressing beyond expectations, considering the difficulties of the times. Al-
though the arrangement of the sessions and the scheduling of the papers in the
sessions have not yet been completed, the Papers Committee is pleased to present
the following list of titles that will be included. Accompanying a number of the
papers will be film presentations and demonstrations. The names of authors
omitted from the following list will be given in the Tentative and Final Programs.
Some of the presentations will be given at the studios, and at least one or pos-
sibly two afternoons will be left free for diversion or other interests.
"Single Film Portable Recording Systems" ; RCA Victor Division, Radio Corpora-
tion of America.
"Sound Installations in Washington"; RCA Victor Division, Radio Corporation

of America.
"Accoustical Research Facilities at the RCA Princeton Laboratories"; Radio

Corporation of America.
"New Duplex Loud Speaker"; J. B. Lansing, Altec-Lansing Corp., Hollywood,

Calif.
"High-Quality Communication and Power Transformers"; Ercell B. Harrison,

Altec-Lansing Corp., Hollywood, Calif.
"250-Watt Class-B Audio Amplifier"; John W. Hilliard, Altec-Lansing Corp.,

Hollywood, Calif.

"Post- War Television Planning and Requirements"; Klaus Landsberg, Tele-
vision Productions, Paramount Studios, Hollywood, Calif.

Sept., 1943 J FIFTY-FOURTH SEMI-ANNUAL CONFERENCE 267

"A Simplified Variable- Density Sound Developer"; Paul Zoff and F. J. Twining,
Columbia Pictures Corp., Hollywood, Calif.

"Walt Disney Studio— a War Plant"; Carl Nater, Walt Disney Studios, Burbank,
Calif.

"Present and Proposed Use of Plastics in the Motion Picture Industry"; Barton
H. Thompson, Paramount Pictures, Inc., Hollywood, Calif.

"Sixteen-Mm Color to 35- Mm Black-and- White" ; Carroll H. Dunning, Dunning
Process Co., Hollywood, Calif.

"The Future of the 16-Mm Sound-Film Industry"; John A. Maurer, J. A.
Maurer, Inc., New York, N. Y.

"What to Expect of Direct 16-Mm"; Lloyd Thompson, The Calvin Company,
Kansas City, Mo.

"Improvements in Sound Recording Equipment"; L. F. Brown, ERPI Division
of the Western Electric Company, Hollywood, Calif.

"A New Sound Reproducer"; ERPI Division of the Western Electric Company,
Hollywood, Calif.

"A New Single-Film Recording Camera"; George Worrall, Mitchell Camera
Company, Hollywood, Calif.

"Duplication of Kodachrome Original, with Enlargements, Reduction, and Color
Correction"; Earl Morgan and Roy Peck, Paramount Pictures, Inc., Holly-
wood, Calif.

"Transfer of Kodachrome Emulsion to Lantern-Slide Glass"; Barton H. Thomp-
son, Paramount Pictures, Inc., Hollywood, Calif.

"High-Efficiency Stereopticon Projection for Color Background Shots"; A. C.
Zoulis and Farciot Edouart, Paramount Pictures, Inc., Hollywood, Calif.

"A 200-Mil Push-Pull Sound- Recording System"; L. D. Grignon and J. P. Cor-
coran, Twentieth Century-Fox Film Corp., Hollywood, Calif.

"A Visual Light- Valve Checking Device"; J. P. Corcoran, Twentieth Century-
Fox Film Corp., Hollywood, Calif.

"Improvements in the Disney Scoring Stage"; C. O. Slyfield, Walt Disney Pro-
ductions, Burbank, Calif.

"Improvements in the Columbia Scoring Stage"; J. Livadary, Columbia Pic-
tures Corp., Hollywood, Calif.

"New Scoring Stage, Shell, and Vocal Booth Design"; Loren L. Ryder, Para-
mount Pictures, Inc., Hollywood, Calif.

"Combination 16-Mm Contact and Optical Printer"; Irving B. Dyatt, Oregon
State College.

"A High-Speed Method of Controlling Kelvin and Light Intensity for Motion
Picture Printers"; Irving B. Dyatt, Oregon State College.

"Modern Processes of Color Photography"; Joseph S. Friedman.

"Cunningham Combat Camera"; Harry Cunningham, RKO Studies, Hollywood,
Calif., and Capt. E. H. Fehnders, U. S. Army Signal Corps.

"Improvements in 16-Mm Equipment"; Commander Alfred Gilks, Office of
Strategic Supplies, Field Photographic Branch.

"The Work of the Training Film Branch, Photographic Division, Bureau of Aero-
nautics, U. S. Navy"; Lt. Orville Goldner, U. S. N. R., Washington, D. C.

"Production Planning for Navy Training Films"; Lt. R. B. Lewis.

268

FIFTY-FOURTH SEMI-ANNUAL CONFERENCE

"Making Films That Teach"; Lt. Reginald Bell, Training Film Branch, Bureau

of Aeronautics, U. S. Navy.
"The Training Film Program in Action"; Training Film Branch, Fire Control

School, Navy Yard, Washington, D. C.

IMPORTANT

Hotel reservation cards must be re-
turned immediately. Otherwise the
Hotel cannot guarantee accommoda-
tions.

SOCIETY ANNOUNCEMENTS

AMENDMENTS OF THE BY-LAWS

At the meeting of the Board of Governors held at Hollywood on June 4th the
following proposed amendments of the By-Laws were approved for submittal
to the membership of the Society for voting at the Fifty-Fourth Semi-Annual
Technical Conference, to be held at Hollywood October 18th to 22nd, inclusive.

Proposed Amendment of By-Law IV, Sec. 4(b)

To the list of standing Committees appointed by the Engineering Vice-President
shall be added the Committee on Test- Film Quality.

Proposed Amendment of By-Law IV, Sec. 5

Two Admissions Committees, one for the Atlantic Coast Section and one for
the Pacific Coast Section, shall be appointed. The former Committee shall
consist of a Chairman and six Fellow or Active members of the Society, residing
in the metropolitan area of New York, of whom at least four shall be members of
the Board of Governors.

The latter Committee shall consist of a Chairman and four Fellow or Active
members of the Society residing in the Pacific Coast area, of whom at least three
shall be members of the Board of Governors.

MAILING OF NOTICES TO MEMBERS OF THE
ATLANTIC COAST SECTION

As the territory included by the Atlantic Coast Section of the Society extends
from Maine to Florida and includes the Eastern and Central Standard Time
zones (as the result of the discontinuance of the Mid-West Section), many of the
members of the Section find it impossible to attend the monthly meetings and
other functions. The situation has been considerably aggravated by the present
difficulties of transportation.

269

S. M. P. E. TEST-FILMS

These films have been prepared under the supervision of the Projection
Practice Committee of the Society of Motion Picture Engineers, and are
designed to be used in theaters, review rooms, exchanges, laboratories,
factories, and the like for testing the performance of projectors.

Only complete reels, as described below, are available (not short sections
or single frequencies). The prices given include shipping charges to all
points within the United States; shipping charges to other countries are
additional.

35-Mm. Sound-Film

Approximately 500 feet long, consisting of recordings of several speak-
ing voices, piano, and orchestra; buzz-track; fixed frequencies for focus-
ing sound optical system; fixed frequencies at constant level, for de-
termining reproducer characteristics, frequency range, flutter, sound-
track adjustment, 60- or 96-cycle modulation, etc.

The recorded frequency range of the voice and music extends to 10,000
cps. ; the constant-amplitude frequencies are in 15 steps from 50 cps. to
10,000 cps. Price $37.50 each.

35-Mm. Visual Film

Approximately 500 feet long, consisting of special targets with the aid
of which travel-ghost, marginal and radial lens aberrations, definition,
picture jump, and film weave may be detected and corrected. Price
$37.50 each.

16-Mm. Sound-Film

Approximately 400 feet long, consisting of recordings of several speak-
ing voices, piano, and orchestra; buzz-track; fixed frequencies for focus-
ing sound optical system; fixed frequencies at constant level, for de-
termining reproducer characteristics, frequency range, flutter, sound-
track adjustment, 60- or 96-cycle modulation, etc.

The recorded frequency range of the voice and music extends to 6000
cps.; the constant-amplitude frequencies are in 11 steps from 50 cps. to
6000 cps. Price $25.00 each.

16-Mm. Visual Film

An optical reduction of the 35-mm. visual test-film, identical as to
contents and approximately 225 feet long. Price $25.00 each.

SOCIETY OF MOTION PICTURE ENGINEERS

HOTEL PENNSYLVANIA

NEW YORK, N. Y.

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

VOLUME XLI • • • OCTOBER, 1943

CONTENTS

PAGE

The General Electric Television Film Projector

E. D. COOK 273

Report of the Committee on Sound 292

A Note on the Projection Life of Film

D. R. WHITE AND C. DEMoos 297

Some Characteristics of Ammonium Thiosulfate Fixing
Baths D. B. ALNUTT 300

The Motion Picture in the Service of the Army Air Forces

L. CARR 329

A Compact Production Unit for Specialized Film

O. W. HUNGERFORD 332

Discussion of Industry Problems E. KUYKENDALL 336

Some Suggested Standards for Direct 16-Mm Production

L. THOMPSON 340

Resistance of Glass to Thermal SJiock C. D. OUGHTON 351
Current Literature 358

The Fifty-Fourth Semi-Annual Technical Conference of
the Society, Hollywood, Calif., October 18-22, 1943 360

(The Society is not responsible Jor statements of authors.)

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

HARRY SMITH, JR., EDITOR
ARTHUR C. DOWNES, Chairman

Board of Editors

JOHN I. CRABTREE ALFRED N. GOLDSMITH EDWARD W. KELLOGG
CLYDE R. KEITH ALAN M. GUNDELFINGER CHARLES W. HANDLE Y

ARTHUR C. HARDY
Officers of the Society
** President: HERBERT GRIFFIN,

90 Gold Street, New York, N. Y.
"Past-President: EMERY HUSE,

6706 Santa Monica Blvd., Hollywood, Calif.
** 'Executive Vice-President: LOREN L. RYDER,
5451 Marathon Street, Hollywood, Calif.
*Engineering Vice-President: DONALD E. HYNDMAN,

350 Madison Avenue, New York, N. Y.
** Editorial Vice-President: ARTHUR C. DOWNES,

Box 6087, Cleveland, Ohio.
* Financial Vice-President: ARTHUR S. DICKINSON,

28 W. 44th Street, New York, N. Y.
**Convention Vice-President: WILLIAM C. KUNZMANN,

Box 6087, Cleveland, Ohio.
^Secretary: E. ALLAN WILLIFORD,

30 E. 42nd Street, New York, N. Y.
^Treasurer: M. R. BOYER,

350 Fifth Ave., New York, N. Y.
Governors

*H. D. BRADBURY, 411 Fifth Avenue, New York, N. Y.
*FRANK E. CARLSON, Nela Park, Cleveland, Ohio.
*ALFRED N. GOLDSMITH, 580 Fifth Avenue, New York, N. Y.
*A. M. GUNDELFINGER, 2800 S. Olive St., Burbank, Calif.
*CHARLES W. HANDLEY, 1960 W. 84th Street, Los Angeles, Calif.
*EDWARD M. HONAN, 6601 Romaine Street, Hollywood, Calif.
*JOHN A. MAURER, 117 E. 24th Street, New York. N. Y.
**WILLIAM A. MUELLER, Burbank, Calif.

**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood, Calif.
**H. W. REMERSHIED, 716 N. La Brea St., Hollywood, Calif.
** JOSEPH H. SPRAY, 1277 E. 14th Street, Brooklyn, N. Y.
**REEVE O. STROCK, 195 Broadway, New York, N. Y.

*Term expires December 31, 1943.
**Term expires December 31, 1944.

Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.

Publication Office, 20th & Northampton Sts., Easton, Pa.

General and Editorial Office, Hotel Pennsylvania, New York, N. Y.

Entered as second-class matter January 15, 1930, at the Post Office at Easton,

Pa., under the Act of March 3, 1879. Copyrighted, 1943, by the Society of Motion

Picture Engineers, Inc.

Frank H. Richardson

As the October Journal goes to press we learn with sorrow of
the death of Frank H. Richardson, Fellow of the Society and a
member since its founding in 1916. We have lost a loyal and
active associate whose devoted interest in the welfare of the Society
will long be remembered.

The Society of Motion Picture Engineers

Its Aims and Accomplishments

The Society was founded in 1916, its purpose, as expressed in its
Constitution, being the "advancement in the theory and practice of
motion picture engineering and the allied arts and sciences, the stand-
ardization of the mechanisms and practices employed therein, and the
maintenance of a high professional standing among its members."

The membership of the Society is composed of the technical experts
in the various research 'laboratories and other engineering branches of
the industry, executives in the manufacturing, producing, and exhibit-
ing branches, studio and laboratory technicians, cinematographers,
projectionists, and others interested in motion picture engineering.

The Society holds two conventions a year, spring and fall, at various
places and generally lasting four days. At these meetings papers
dealing with all phases of the industry — theoretical, technical, and
practical — are presented and discussed, and equipment and methods
are often demonstrated. A wide range of subjects is covered, many
of the authors being the highest authorities in their particular lines
of endeavor. On occasion, special developments, such as the SMPE
Visual and Sound Test-Films designed for the general improvement
of the motion picture art, are placed at the disposal of the member-
ship and the industry.

Papers presented at conventions, together with contributed articles,
translations, and reprints, and other material of interest to the motion
picture engineer are published monthly in the JOURNAL of the Society.
The publications of the Society constitute the most complete existing
technical library of the motion picture industry.

THE GENERAL ELECTRIC TELEVISION FILM PROJECTOR
ELLSWORTH D. COOK**

Summary. — In the following paper, the General Electric television motion picture
film projector is described by its designer. Certain of the design objectives and some
of the special problems involved are discussed. A mong these problems is the projec-
tion of standard motion picture film at thirty television frames per second without
change in sound quality. The theory and construction of the intermittent movement
are given and views are shown of the projection equipment as installed in the General
Electric Television Station WRGB.

Because of the great amount of time necessary for the rehearsal of
each new act, the rapid exhaustion of available subject material, and
the general interest in news events, it is thought that much of the
subject material for commercial television programs will be obtained
from current motion picture films as soon as widespread use is made
of this facility.

The operational standards chosen for television have made it
necessary to redesign or modify existing motion picture projection
equipment, at least at the beginning of television broadcasting.
This condition is likely to continue since it does not seem practical to
finance "retakes" of the desired subject material or that motion
picture producers would be willing to revise their equipment to fit
new standards, particularly since they have just passed through
one such major and expensive revision in connection with sound
recording.

The present standard television picture is formed by an elementary
spot of light of varying brilliancy moving across the picture frame
in parallel lines. Since there are 525 approximately horizontal lines
for each television picture, and since the picture is formed by first
traversing the odd-numbered lines and then the intermediate even-
numbered lines, it is evident that the detail of the picture would
suffer if, for any reason, these alternate lines should overlap. It

* Presented at the 1942 Spring Meeting at Hollywood, Calif.
"* General Engineering Laboratory of the General Electric Company, Sche-
nectady, N. Y.

273

274 E. D. COOK [J. S. M. P. E.

has been thought that the limit of any displacement between the
alternate lines should be equal to one-half of their relative spacing.
Thus, a vertical displacement of approximately Vio of one per cent
would represent a practical, superior limit for any such motion.
Since, as will be seen later, the odd-numbered lines of certain definite,
television pictures may be obtained from one individual frame or
picture of a motion picture film, while the even-numbered lines
may be obtained from the following frame, it will be evident that a
logical specification for the accuracy of registration of succeeding
pictures thrown upon the reproducing screen by the motion picture
projector would be this same figure, Vio of one per cent, as an upper
limit. Naturally, such a specification would assume that equal ac-
curacy will be found throughout the entire television system re-
sponsible for the line structure, as well as in the motion picture
camera and printer, and that a proper film, once made, could be main-
tained if such performance is to be effectively employed.

A careful consideration of the requirements for speed constancy
and experience with the possibilities of the better forms of me-
chanical filters in this field reveal that in the matter of construction
to meet the desired specification, the advantages should lie with
the intermittent type of projector rather than with the so-called
"continuous motion projector." In fact, the problem of film shrink-
age alone would be sufficient to cause the experienced designer to
prefer the former type of machine.

This paper is a description of the G-E standard 35-mm motion
picture projector development for television service. This project
was started in March, 1938, and two of the projectors described
have been in use since December of that year. Because of its de-
sign, the E-7 Simplex Projector was chosen and modified to suit
the special conditions peculiar to this field. The operating side of
the projector is shown in Fig. 1.

It has been standard practice in television to use a frame frequency
which is a sub-multiple of the frequency of the supply voltage, for
instance, 30 per second, because of any possible residual hum in
rectified d-c voltage supplies. The present standard sound motion
picture practice utilizes a frame frequency of 24 per second. In order
to bring these two standards into agreement so that standard sound
motion picture film may be used, it is necessary to employ a varying
frequency of projection so that the average frequency may remain
24 film frames per second. This is possible if the instantaneous

Oct., 1943]

TELEVISION FILM PROJECTOR

275

projection speed alternates between 30 and 20 frames per second in
such a manner that the average film speed may remain 24 frames
per second.

Since the slower instantaneous projection frequency would leave
a given film frame in the projection aperture for a time interval that
would be fifty per cent greater than that for the higher projection

FIG. 1. The General Electric television motion picture film pro-
jector.

frequency, it will be evident that any mechanical movement, which
will project two film frames for each complete revolution of its drive
shaft in such a manner that each film frame will remain in the pro-
jection aperture the necessary length of time and one will remain
fifty per cent longer than the following film frame, may be used for
this purpose. This may be easily understood by reference to Fig. 2

276

E. D. COOK

[J. S. M. P. E.

which shows the time cycle of events in the standard motion picture
sound-film and the same film as used in television.

It will be essential that the drive shaft to the intermittent move-
ment in question rotate at the same speed that an otherwise stand-
ard motion picture device would be forced to use to project two

NUMBER
OF
FILM
FRAME

STANDARD
SOUND
FILM
CYCLE

ELAPSED] NUMBER

TIME | OF
IN .TELEVlSIOn
SECONDS FRAME

TELEVISION CYCLE
FOR
STANDARD FILM
WITH 7.570
ILLUMINATION TIME

ELAPSED
TIME
IN
SECONDS

ILLUM.

.OOOO

ILLUM.

.01 04

DARK

SCAN

0 1 67

.0208

ILLUM.

O 1 79

ILLUM.

.0313

XDARK a SCAN//
^ a //

MOVE 1 FILM FRAME

///n ' L* /. / /s

0333

// ft V/

ILLUM.

0346

/^MOVE.//^

..0417

DARK

ILLUM.

.0521 2

SCAN

.05OO

DARK

.0625

DARK

.05 1 3

SCAN

0667

ILLUM.

.0729

•///r\/o ' a? e^ ' ' '' /

^0*a^

J0833 ,

// a x^

MOVE 1 FILM FRAME

ILLUM.

.0938

DARK

SCAN

1 GOO

.1042

ILLUM.

1 O 1 3

ILLUM.

.1 146

/'DARK V SCAN^
MOVE 1 FILM FRAME

.1167

/, OL //

ILLUM.

1179

•%MOVE///

.1250

DARK

ILLUM.

SCAN

.1 333

ILLUM

1 346

DARK

. 1458

DARK

SCAN

1 5OO

ILLUM.

1513

!«?£!

. 1667

/DARK a S'CAN"/^/

MOVE 1 FILM FRAME

IP67

FIG. 2.

Time cycle comparison for motion picture film in
television and theater projectors.

film frames per revolution of the equivalent shaft. In the usual
projector (and this applies to the standard model E-7 used here) only
one frame is projected per revolution. Hence, this drive shaft
normally revolves at 1440 rpm.

In the design of the modified machine, this would call for the inter-

Oct., 1943] TELEVISION FILM PROJECTOR 277

mittent drive shaft to operate at a steady speed of 720 rpm with
projection occurring at a reference point and again 144 degrees
later for each revolution; i. e., each revolution is divided into parts
respectively of 2/5 and 3/5 in duration. Such a design would produce
a severe screen flicker and if this is to be avoided, the number of
pictures projected per second would have to be increased. This
may be accomplished if the viewing time of such a sequence of opera-
tions is interrupted, as in standard motion picture operation.

If two views of the same picture are to be seen during the 2/5 por-
tion of the cycle, three views of the next film frame will be seen dur-
ing the remaining 3/5 portion of the cycle. Therefore, it is obvious
that the intermittent film motion could not be permitted to utilize
90 mechanical degrees of the intermittent drive shaft rotation. This
is important, since it rules out the standard form of Geneva motion.

r «a* ^ n

FIG. 3. Disassembled view of intermittent in General Electric television pro-
jector.

It was mentioned previously that in present television practice
in the United States, which practically presupposes the use of cath-
ode ray tubes, the picture is "painted" by a flying spot of light of
varying intensity that moves across the field in approximately hori-
zontal lines, and that each of the successive elementary pictures is
composed of the alternate lines, respectively. This succession of
events occurs in such a way that these elementary pictures follow
one another at a rate of 60 per second, being interlaced with a maxi-
mum time interval of eight per cent between them, according to the
present standards. It is within this short time interval that the
film will be illuminated, and if a blurred picture is to be avoided,
the film must be at rest during the period of illumination.

Thus, the complete operation for each individual or elementary
television picture must be confined to 72 degrees of mechanical ro-
tation of the intermittent drive shaft, while the motion of the film

278 E. D. COOK [j. S. M. P. E.

at the projection aperture must be completed in 66.24 degrees of
rotation of this same shaft, if the projector is to be synchronized
with the flying spot. One of the simplest movements known that
can operate with this reduced angle of motion and give a high degree
of registration, is the Powers movement. This is essentially a face
cam. The intermittent sprocket shaft terminates in a plate with
four pins located on a square so that two slide on the outer cam
surface and two slide on the inner cam surface. A disassembled
view of the intermittent movement may be seen in Fig. 3. The
principle is covered by the patent issued to A. V. Bedford (U. S.
2,082,093).

It is noted that the drive shaft and cam wheel operate in the
same direction for outside cams which were preferred in this case.
Since the relative of these two parts is the reverse of the Geneva
motion, which it will now replace, the direction of the cam shaft
would have to be reversed. It was found possible to add an idler
gear inside the intermittent casting to accomplish this. The theory
of design for the Powers cam will be explained later.

Since the television picture has 60 elementary views per second,
it is evident that the shutter speed must be modified to synchronize
it with the film cycle. The permitted speeds are sub-multiples of
3600 rpm.

If the shutter shaft is to remain in its present position, the ad-
vantages of larger shutter diameters are not available. Based on a
given percentage of time allotted to the illumination of the film in a
given shutter system, the size of the shutter opening is determined
by the shutter speed. If the shutter opening is smaller than the
diameter of the cone of light at the shutter plane, it becomes a limita-
tion on the amount of light that can be passed by the optical system.
Hence, it is an advantage in a disk shutter to use a single aperture
and operate at 3600 rpm. In this case, it was found that for the
diameter of shutter which can be accommodated, the shutter was the
limiting aperture. In spite of this, calculation and subsequent
experience have revealed that ample margin in illumination is avail-
able for the iconoscope.

The shutter aperture, as originally chosen, was seven per cent,
hence the remainder of the time allowed for the television spot to
pass through one vertical retrace operation is available to overcome
any mechanical trouble due to back-lash or transients which might
exist in any other part of the equipment.

Oct., 1943] TELEVISION FILM PROJECTOR 279

The E-7 Simplex projector is normally equipped with 1440 rpm
front and rear shutters. In normal motion picture operation, this
design permits greater illumination on the screen and a cooler film.
The rear shutter was originally equipped with a fan. The fan was
omitted in the modified design, employing 3600 rpm shutters be-
cause of the excessive power requirements. Fortunately, heating
is not a problem in the projector optical system for television service.

With the new intermittent motion, space limitations would have
prevented as much framing correction as permitted in the standard
E-7 Simplex projector, but the primary reason for this adjustment
has largely disappeared in first-class projection rooms. Its inclusion
in a standard projector is due primarily to the fact that certain

FIG. 4. Disassembled view of shutter-shaft driving system for General Elec-
tric television projector.

theaters, which may purchase new projectors, often receive film
which is badly mutilated or hire operators who frequently do not
attempt to maintain the careful projection practice demanded in
higher grade theaters.

The use of the framing adjustment is dependent upon careless-
ness, either in the splicing or the inspection of the film before "run-
ning" a show or in "threading." Television, as a new industry in
which each transmitter hopes to reach thousands of observers, can
hardly expect to employ operators who are less careful than those
of the better theaters. "Threading" mistakes would be pure care-
lessness with both a framing and a threading lamp especially pro-
vided to make inspection of framing a simple matter during thread-

280

E. D. COOK

[J. S. M. P. E.

ing. Furthermore, television should not countenance the use of
film so badly mutilated that missing sprocket holes permit the pic-
ture to get out of frame after being correctly threaded ; in fact, it is
likely that the television studio will insist on first-run film because
of the very serious loss in definition that will exist for even the smallest
wear at the sprocket-holes or abrasion of the film. The former point
will be more fully appreciated when it is realized that a vertical dis-

FIG. 5.

Skeleton assembly view of shutter-shaft driving system
for General Electric television projector.

placement of the film in the projection aperture of only 0.0014 inch
from its correct position is equivalent to a shift in the television
picture of one scanning line pitch. Such motion is twice the limit
previously mentioned as a desirable upper limit.

A direct drive from the main drive shaft to the shutter shaft was
used in order to relieve the projector gears and stud shafts of the
shutter load, and to reduce the possibility of excessive speed variation
in the shutter motion that would otherwise exist due to back-lash in

Oct., 1943] TELEVISION FILM PROJECTOR 281

the gear train. These two factors were found to be of considerable
importance. Since the motor operates at 1800 rpm, a two-to-one
increase in speed was made necessary by the use of the 3600 rpm
shutter.

Experience showed that this design, in addition to improving the
safety factor on the projector gears, permitted quieter operation
than would have been possible with any back-geared arrangement
on the original shutter shaft, and permitted rapid starting time
Experience has also shown that with the direct shutter drive it re-
quires about three to four seconds to synchronize fully the motor
with the line, but it is conceivable that this may vary somewhat.

In order to accomplish this, two things were necessary: (1) the
original shutter-shaft drive gear on the oblique shaft in the picture
head was removed and (2) a special sound head drive shaft with an
extension on the coupling end was employed. The latter permitted
a vertical shaft to be located just in front of the sound-head and
projector casting. A special adapter was fastened to the sound-
head gear box. This was designed to employ a ball bearing to sup-
port the sound-head drive shaft adjacent to the one-to-two spiral
gears that were used to drive the vertical shutter shaft from the
sound-head drive shaft. These gears were hardened and designed
to operate in an oil bath. The component parts used to drive the
shutter shaft by means of an external drive shaft are shown in
Fig. 4, and a skeleton assembly of these parts is shown in Fig. 5.

A spacing bracket was fastened between the sound-head and the
usual motor base bracket to accommodate the gear box for the
vertical shaft. The flexible coupling originally employed between
the motor and the sound-head drive shaft was used as before.

The splined gear and the spline assembly found on the original
shutter shaft were removed, and an adapter was added to fit within
the existing spline housing that is bolted to the main projector
frame. An extended shutter bearing housing, as shown in Fig. 5,
was designed to pass through the front casting of the projector
head and clamp in this adapter. This established a rigid front
support for the shutter shaft by the use of two sealed ball bearings
at the front shutter end of this extended bearing housing and, like-
wise, accommodated a ball bearing for the upper end of the 3600-
rpm vertical shutter drive shaft. Hardened spiral gears, operating
in an oil bath, were used between the vertical drive and the shutter
shafts. The ratio of speeds at this point was one-to-one. Special

282

E. D. COOK

[J. S. M. P. E.

attention has been given to means of preventing the rapid leakage of
oil from the oil wells at each end of the vertical shaft. Oil cups
were added to make daily inspection and filling of these oil wells to
the proper level a simple matter.

Several additional considerations of a minor nature will be found
in the problem of adapting the E-7 Simplex projector to television
service; for example, the iconoscope screen position and the toler-
ances in its size forced the use of a longer focal length lens than is
ordinarily used. The lens chosen for this purpose was provided

FIG. 6. Driving gear system for General Electric television pro-
jector.

with a reduced rear-barrel diameter. Therefore, a special adapter
was required in the rear lens mount to clamp that portion of the pro-
jection lens which had a reduced diameter.

The projection lens should place an image of the rear shutter on
the front shutter, if the latter is to cut off all of the remaining light
passed by the rear shutter when both have their corresponding
aperture edges on the optical axis. The preliminary design cal-
culations indicated that an exact focus would require an impractical
extension of the front end of the shutter shaft. However, since the
image of the rear shutter aperture edge produced by the projection

Oct., 1943]

TELEVISION FILM PROJECTOR

283

lens was not too poor at the present front shutter position, and since
some margin in closing time exists, no modification was felt de-
sirable. Tests on the finished machine showed acceptable per-
formance for both the opening and closing operation of these shutters
as far as they were affected by focus of one upon the other.

In order to prevent accidents, the front shutter housing apertures
were covered with glass. Although this is not done in professional
use, it was thought desirable here in spite of the extra glass to air
surfaces in the optical path. These windows also aid slightly in

FIG. 7. Diagram showing geometry of intermittent cam system.

noise-reduction. Although the loss of light is not serious, there is
a small amount of scattered light due to reflection at these surfaces.
For this reason, they have been made removable.

Another optical problem was found in the attempt to focus accu-
rately the projection lamp on the projection lens. This was due to
the diameter of the lamp bulb. Since operating results have shown
that a satisfactorily uniform field of illumination could be obtained
at the iconoscope mosaic, no change in the standard condenser sys-
tem was felt necessary.

It was said that for average lighting in normal operation at least

284 E. D. COOK [J. S. M. P: E.

25 foot-candles would be required on the iconoscope mosaic, but
subsequent advice from the manufacturer of the iconoscope stated
that "satisfactory operation should be possible with a level of 1.5
millilumens per square centimeter for average conditions, and 3.5
millilumens per square centimeter for high light conditions." Cal-
culations showed that the 900-watt, T-20 projector lamp was ca-
pable of supplying this level under ordinary film conditions with at
least a two-to-one safety factor. Subsequent measurements con-
firmed this. It was to make this possible that the 3600-rpm shutter
was originally chosen. The alternative would have been an arc
lamp, since incandescent sources of higher illumination were not
available.

FIG. 8. Assembly view of intermittent for General Electric tele-
vision projector.

Measurements of the mechanical power requirements showed that
a rating of approximately 1/8 hp would be required. A 3-phase,
220-volt, self-synchronous motor of this rating was used. With
the larger motor, the moment of inertia of the flywheel was increased
to reduce the shock due to starting acceleration, as well as any
possible effects of shocks from the power system.

To further reduce the starting acceleration, adjustable 10-ohm pro-
tective resistors were used in each of the 3-phase lines. To make
certain that full-line voltage would not be applied to the motor too
soon, a time delay relay and contactor are used to short circuit the
line resistors after the motor is synchronized with the line supply.

Oct., 1943]

TELEVISION FILM PROJECTOR

285

However, should this relay fail to short the line resistors, no loss of
synchronism will result.

The synchronous motor was equipped with a d-c field winding of
approximately 150 ampere turns per pole to automatically phase
the projector with the electrical power system and, hence, the elec-
trical impulses used to effect scanning.

As a final modification, means for anchoring the outer end of the
stud shafts on both the main drive gear and the coupling gear, be-
tween the sound-head and the projector, has been provided. This
may be seen from Fig. 6 which shows the gear train of the projector
and sound-head.

Since it was found possible to use the main casting of the Geneva
intermittent system in which the distance between the sprocket
shaft (which was coaxial with the drive shaft) and the cam shaft
was 0.7495 inch, one dimension b (Fig. 7) of the Power's intermittent

IZOV

FIG. 9.

TRANSFORMER
15 X

Schematic connection diagram for projection lamp in General
Electric television projector.

was determined. As a trial, the distance 5 between the centers of
the locking pins was chosen as an even dimension, but was later
changed to improve the design.

It was decided to employ a sine wave accelerating motion of the
film, primarily because the angle of pull-down was less, in this case,
than in the standard Geneva intermittent; and secondarily, to
reduce any effect of film motion that might be revealed by slightly
incorrect adjustments in the shutter, as well as back-lash in drive
gears. Thus, the velocity of the sprocket shaft would be slow during
the beginning and ending phases of this motion, but the cam would
be called upon to work hardest in the middle of the moving cycle.

Design of the Intermittent Movement. — If two film frames are re-
quired for one revolution of the cam shaft then, as previously ex-
plained, only 144 degrees can be allotted to the shortest cycle, and if
this frame of film is to be shown twice during this time with a maxi-

286

E. D. COOK

[J. S. M. P. E.

mum allowance of eight per cent for the upper limit of time of illu-
mination, the central angle of the cam allotted to film motion can be
only 66.24 degrees. Therefore, if (w) is the displacement of the
cam wheel and (a) is the angular displacement per cycle of an inter-
mittent sprocket that accommodates four film frames per revolution,
it can be seen that for sine wave film motion (see Fig. 7) :

a = 45 [1 - cos (2.7173)]

(1}

TO PROJECTOR

Hf\ND

WHEEL.

5WITCH "

ON PROJECTOR

PEDESTAL.

FIELD TO BE 05E.D
DURING SYCHRONIZING
TIME ONLY.

CONTACTOR CR-3.&U-C2D
CAT. 43SG931GIO3 WITH
CO\L CONNECTED AS SHOWN.

FIG. 10. Schematic connection diagram of motor starting circuit for
General Electric television projector.

Hence

0 = (45+ a)
ft = (45 - a)

Once 5 is chosen, it is obvious that

(2}

(3}

In the design, the diameter of the pins d was chosen as 0.1000
inch. The outer radius of the cam wheel RI can be determined from

and the inside radius R* may be calculated from eq. 5

+ »-*> +

(4)

(5)

Oct., 1943]

TELEVISION FILM PROJECTOR

287

The design of the actuating surfaces of the cam involves the re-
peated solution of eqs. 6 and 7 for small increments of displacement
Aw, in this case 1 degree each

cos 0

FIG. 11.

Motor starting equipment for General Electric television
projector.

+ b* + V%Sb cos 0

(7)

To complete the design of the cam wheel the other coordinates
for both TI and r4 must be calculated. This may be accomplished
by determining the included angle X between these two vectors,
then the angle between either and the central vector b, for ex-
ample, 5.

288
Thus

E. D. COOK

5i = arc cos

[J. S. M. P. E.
(*)

(3)

From these equations all of the necessary details for the construc-
tion of the cam wheel and pin wheel can be obtained.
The completed cams worked very well requiring no more power

PMOTi*

EXTERNAL. WIRING.

rLOW CAPAOTY CABLE".

ELECTR.IC CC-LU TRANS Fo^Me»?. (RXA-CAT.

5oo OHM UINE

use

ACROSS PHOTO ei_ec.TRic.
ecu. »ATTe«Y IP
urxvos ARE L^>H

3o VOLTS

FIG. 12. Schematic connection diagram for sound system in Gen-
eral Electric television projector.

than the intermittent system they replaced, and producing a screen
picture of exceptional steadiness. An assembled view of the inter-
mittent movement may be seen in Fig. 8.

The Sound Head. — The sound-head used was the Simplex design
employing the RCA Rotary Stabilizer. It utilizes a single stage
of mechanical filtering to reduce the variations in film velocity,
at the sound scanning point, to an acceptable amount. Since this
device has been previously described before the Society, no further

Oct., 1943]

TELEVISION FILM PROJECTOR

289

description will be given here. For the mathematical theory the
reader may refer to a previous article by the author, "The Technical
Aspects of the High-Fidelity Reproducer" (J. Soc. Mot. Pic. Eng.,
XXV (Oct., 1935), p. 289).

The operation of this form of sound-head has been very satis-

FIG. 13. Film projection room in General Electric television Studio

WRGB.

factory. Although better designs are possible, it was felt that the
economy of commercially available devices more than offsets the
difference in performance.

The only modification necessary was to have the sound-head
supplied with the special shaft previously mentioned having, in
addition, the proper gear reduction for an 1800-rpm or synchronous

290

E. D. COOK

[J. S. M. P. E.

motor rather than for the 1750-rpm induction motor generally sup-
plied. The adapter, etc., necessary to drive the vertical shaft geared
to the shutter shaft has been previously described.

Electrical Features. — The filament of the projection lamp is sup-
plied from a step-down transformer and preferably should be

Fic.j]14. Television film camera room in General Electric television
Studio WRGB.

brought to normal voltage (30 volts) slowly. There are several
methods by which this may be accomplished, but a simple variable
series resistance of approximately 15 ohms, 10-ampere rating, in the
primary circuit of the transformer, seems as economical and satis-
factory as any. The wiring diagram, which may conveniently in-
clude the switch at the rear of the projector pedestal, is shown in

Oct., 1943] TELEVISION FILM PROJECTOR 291

Fig. 9. If desired, the filament transformer may be mounted within
the pedestal.

Adjustable protective resistors have been specified in the 220- volt
supply lines for the 3-phase synchronous motor. These resistors
limit the initial starting voltage to that just capable of starting the
motor. As previously mentioned, a time delay relay and contactor
have been provided to automatically short circuit these resistors.
The connection diagram is shown in Fig. 10. A photograph of the
starting box, including the three protective resistors, the time delay
relay, and the contactor, is shown in Fig. 11.

A framing light, which is used to determine whether or not the
film is properly framed in the film gate, is located in the demountable
light shield that has been placed between the rear shutter housing
and the film gate. A step-down transformer, 120 to 6 volts, is used
to operate this lamp from any 120-volt, 60-cycle source. The fram-
ing lamp is controlled by a nickel-plated rod found just above the
light shield.

The framing lamp is normally raised above the projection light
beam during normal operation, but upon moving the fire shutter
lift lever forward, the fire shutter is raised and the framing lamp is
automatically switched on and swung down to the optical axis.
Thus, the film frame in the gate will be illuminated with sufficient
intensity for framing inspection purposes.

Since the photoelectric cell is to be transformer coupled to the
amplifier, care should be exercised to keep the electrostatic capacity
of the cable between the photoelectric cell and the primary of the
coupling transformer below 50 mmfds. The photoelectric cell trans-
former should therefore be relatively close to the projector. Due
to its well balanced design and partially shielded location little, if
any, stray field "pick-up" will be experienced. Because of the rela-
tively high overall gain, the photocell transformer should be mounted
to prevent microphonic excitation due to mechanical vibration.
The diagram of connection is shown in Fig. 12.

The motion picture projection room of the General Electric
Company's television studio, Station WRGB, in Schenectady is
shown in Fig. 13, the associated camera room, in Fig. 14.

REPORT OF THE COMMITTEE ON SOUND*

Hollywood sound engineers are currently devoting the major part
of their attention toward maintaining the present quality of sound.
Research and development of new equipment and methods have been
sharply curtailed in some studios and stopped in others for the dura-
tion. However, certain improvement programs are being carried
forward where equipment had been ordered before the war, and where
delivery has been completed.

A number of major sound development projects, which had been
started before the war, have been set aside for the duration. These
projects include further work on stereophonic sound, control track
recording, multiple horn systems, etc.

Economies. — Considerable attention has been given to further
economies in operating techniques and toward the conservation of
strategic materials. The preselection of both picture and sound takes
is being widely employed. By this preselection operation only the
takes which are to be printed are sent to the laboratory for develop-
ment, thereby saving considerable quantities of chemicals in the
developing solutions. Since only one side of the sound negative stock
has been exposed the non-print out-takes are reassembled into 1000-
ft rolls, reversed, and the unexposed edge of this film used for daily
sound prints, leader stock, and other uses. Split film is another
method used for the conservation of film.

The use of dry batteries has been markedly reduced by the conver-
sion of plant equipments to a-c operation.

Vacuum tube types have also been standardized in many equip-
ments.

The following paragraphs outline a number of the features of a
typical Hollywood sound-recording channel as used today :

Microphone. — Directional type microphones are being more widely
used to reduce pick-up from extraneous noise sources and to reduce
acoustic pick-up difficulties inherent in wartime set construction.

Microphone Booms and Poles. — The present trend is to use lighter
weight and more portable booms. The gunning devices have been

* Presented at the 1943 Spring Meeting at New York.
292

REPORT OF SOUND COMMITTEE 293

improved and have made easier the operation of placing the direc-
tional microphone. The use of the "fish-pole" type of mike boom
has increased in recent years. This type of microphone pole consists of
a telescoping "Dural" tube fitted with a standard microphone hanger.
When used on the floor it is either held in the hand of a boom man or
supported by an auxiliary stand similar to a portable lamp stand
which has been fitted with a quiet roller to assist the operator in sup-
porting the boom and in properly directing the microphone. For
high use the pole is equipped with a ring placed near its balance point
by which it may be suspended by a rope from a point directly over
the set. By this means the microphone may be ' 'flown' ' into operating
positions that would be difficult to reach in any other manner. The
use of the fish-pole type of mike boom has proved most expedient for
use on Army location pictures.

Microphone Preamplifiers. — Feedback preamplifiers are replacing
earlier types to reduce noise and to provide better quality. The wide
use of low impedance microphones allows the preamplifier to be
placed at almost any convenient location on the set.

Mixer Control Panels. — The mixer control panel now in general use
is mounted in a portable case along with associate equipment, such as
volume indicator, signal lights, telephone subset, and dialog equal-
izers. This case is usually mounted on a portable wheeled table so
that the operating position may be close to the action to be recorded.
Lighter and smaller equipment components are needed for these mixer
panels to increase further their ease of handling on recording sets.

Booster Amplifiers. — Booster amplifiers are usually mounted in the
mixer case and are used when it is necessary to send the sound cur-
rents some distance to the main amplifier.

Main Amplifiers. — Probably the greatest change in amplifiers in
the past several years has been the advent and adoption of the com-
pressor type or limiting type of main amplifier. By the use of this
amplifier, modulator overshooting, with its inherent distortion, has
been eliminated. Dialog and sound effects of excessive loudness are
now electronically compressed to levels within recording limits.

As in the case of preamplifiers and booster amplifiers, feedback is
being more widely used to increase the signal-to-noise ratio in the re-
cording circuits and to reduce all forms of distortion.

Monitoring Facilities. — The dynamic headset has largely replaced
the monitor booths formerly employed on production stages. The
small plastic molded ear-piece types of headsets are also being exten-

294 REPORT OF SOUND COMMITTEE [J. S. M. P. E.

sively used because of the improved coupling to the ear. Monitor
rooms are used for dubbing and scoring work because of the fixed
nature of these facilities and the need for reverberation characteristics
simulating those of a theater auditorium.

Preequalized Recording of Speech and Music. — Preequalization for
original recordings, both speech and music, is being used by some
sound departments, and a standard preequalization characteristic
is under consideration. No preequalization of the release product is
being considered for the duration.

Recording Machines. — Sound-recording machines have been ma-
terially improved during the past few years. Various types of
sprocketless recording drums of both magnetic and oil-damped types
are being employed to reduce flutter, resulting in a definite improve-
ment in sound quality. Improved fidelity of variable-density re-
corders has also been attained by the use of auxiliary cylindrical lenses
to reduce the effective valve-image height on the film. This improve-
ment effectively eliminates high-frequency intermodulation effects
and increases the signal-to-noise range, since greater valve amplitudes
may be used.

The optical efficiency of recording machines has been improved by
the use of coated lenses. This has been one of the important factors
in promoting the increased use of fine-grain films that require higher
light intensities. Recorders are also being equipped with photo-
graphic slating devices that photograph pertinent information for
each take in the sound-track area. Solenoid operated punches are
also being used for marking the film for preselection purposes.

Automatic starting and stopping circuits are being used by some
studios to start, stop, and synchronize cameras and recorders from a
remote position.

Films for Recording. — The use of fine-grain films for both sound
negative and prints and release positive is now almost universal. The
reduction in film-surface noise has permitted a much higher quality of
reproduction, particularly for critical dialog and musical sequences.

Modulators. — There is an increasing tendency, for original variable-
density recording, toward the use of 200-mil push-pull recording. It
is to be expected that the use of push-pull recording for all original
work will increase in the future. The use of Class B and Class A-B
variable-area track is also finding favor in some of the studios, these
tracks being particularly desirable for super-portable types of record-

Oct., 1943] REPORT OF SOUND COMMITTEE 295

ing channels where the elimination of the weight of the noise-reduction
unit is desirable.

The use of the super-portable type recording channels has proved
advantageous in the recording of Army training films on location.

The resonant rise and high-frequency transients of light- valves are
now being eliminated by the use of electrical feed-back networks that
also provide additional damping for the valve, thereby reducing
transient response. The damping of galvanometers for variable-area
recording by the use of tungsten -loaded rubber has also proved highly
effective.

Re-Recording. — Because original sound-tracks are much improved
by devices such as push-pull track, preequalization, 200-mil tracks and
Class A-B and B tracks, it has become necessary to re-record the
entire sound-track for release purposes. Many unique equalizers,
both automatic and manual in operation, are used throughout to
maintain a standard fidelity.

Film Development Control. — The intermodulation meter for vari-
able-density track and the cross-modulation test for variable-area
track are now being employed universally to establish correct sound-
film development parameters.

Sensitometric control has been standardized throughout the indus-
try by the use of a new electronic densitometer of the intergrating-
sphere type.

Automatic developer replenishment methods are finding wider
use in the laboratories because of the increased uniformity in results
that can be attained.

Recording Stages. — Numerous improvements have been made in
the design of scoring stages for more effective recording of music.
Various types of orchestra shells have been put into service with a
definite improvement in sound quality.

Motor Systems. — Improved test equipment has been designed for
the rapid location of troubles in stage motor systems, particularly
when connected to camera, playback, and transparency equipment.
The slip-clutch type of synchronous distributor is also finding in-
creased use. There is a trend toward the standardization of 1440-
rpm stage drive motors for camera, playback, transparency, and pro-
jector equipment. The handling of transparency projectors is being
expedited by the use of reversible motors so that all picture films may
be rewound to any required sync mark in a minimum of time without
rethreading.

296

REPORT OF SOUND COMMITTEE
COMMITTEE ON SOUND
G. E. SAWYER, Chairman

J. O. AALBBRG
L. A. AICHOLTZ

G. FRIEDL, JR.
E. H. HANSEN

W. C. MILLER
K. F. MORGAN

M. C. BATSEL

L. B. ISAAC

F. ROBERTS

D. G. BELL
D. BLUMBERG
F. E. CAHILL

J. P. LlVADARY

J. A. MAURER

R. McCULLOUGH

H. RUBIN
S. SOLOW
W. V. WOLFE

C. FLANNAGAN

B. F. MILLER

E. C. ZRENNER

A NOTE ON THE PROJECTION LIFE OF FILM*
D. R. WHITE and C. DEMOOS **

Summary. — Tests with intermittent sprockets of different diameters have shown
that the maximum projections which can be attained depends greatly on a diameter
within the range of 0.943 inch to 0.965 inch diameters, about a 21/% per cent range.
The sprocket pitch for best wear is greater than the apparent match between static
perforation measurements and sprocket dimensions. This is in accord with the
view that the elastic characteristics of the base are important at this point in the pro-
jection cycle. Tests with different pressures on the film gate show that this setting is
an important factor affecting wear at the intermittent sprocket. The way by which
perforations tear is different under the following two conditions: (a) film pitch less
than best match for sprocket pitch, and (b} film pitch greater than best match for
sprocket pitch.

The conditions that are required to attain a maximum film life
during projection long have been of interest in the motion picture
industry, but the subject has rarely been of as great importance as
it is today. War conditions have emphasized the importance of all
steps leading to conservation of materials.

Under the most favorable conditions set up in the tests, an average
projection life of 2400 projections was reached. Such a large num-
ber of projections is not commonly attained under commercial con-
ditions. There are many reasons for this: in the first place, many
pictures do not require such a large number of projections* from in-
dividual prints. Such a life would account for nearly twq years of
continuous use, if projected three times per day. It is desirable to
cover the theaters with a greater number of prints effecting shorter
periods from first to last showing than would be achieved if schedules
were worked out on the basis of long, individual print life. In the
second place, accidents in handling in projection and rewind rooms
tend to produce scratches and breaks which mar the film long be-
fore it would deteriorate under laboratory conditions.

The relationship between intermittent sprocket diameter, film
pitch and resultant wear was studied. For the purposes of this
test, the unwind and rewind magazines were removed from a pro-

* Presented at the 1943 Spring Meeting at New York.

** E. I. Du Pont de Nemours & Co., Photo Products Department, Parlin, N. J.

297

298 D. R. WHITE AND C. DE Moos [J. S. M. P. E.

jector and auxiliary idler rolls introduced to permit the continuous
projection of a short loop of film. This arrangement removed all
tension from the pull-down sprocket and, of course, changed condi-
tions at the hold-back sprocket since there was now no tension
corresponding to the normal pull from the wind-up. The relief of
tensions at these points reduced the system to one in which the
chief sprocket-hole wear was clearly traceable to the intermittent
sprocket.

It was not possible to duplicate completely all the various tempera-
ture and humidity conditions which might be encountered in trade
practice, but throughout these tests the arc was used with sufficient
warm-up time to keep the gate and the machine at a normal oper-
ating temperature. The machine was in an air-conditioned room,
and thus the entire system was reasonably reproducible.

Previous experience had shown that only a small departure from
current commercial standards would be required to produce marked
effects on film wear. Accordingly, four sprockets were made:

Sprocket Root Dia. Pitch at Median Line of Film

No. 1 0.943 0.1863

No. 2 0.948 0.1873

-No. 3 0.956 0.1889

No. 4 0.965 0.1907

With this series of sprockets it was possible to show the effect of
relative change in film and sprocket pitch. Results of the first series
of tests are shown in Table I.

TABLE I

Projections with Sprocket
Film Base Film Pitch No. 1 No. 2 No. 3 No. 4

Nitrate— Sample 1 0.1864 360 1251 1070 774

Nitrate— Sample 2 0.1868 365 585 1123 468

Safety— Sample 1 0.1865 90 190 250 162

Safety— Sample 2 0.1863 144 232 380 374

The greatest number of projections attained, as shown in italics
in Table I, shows strikingly that the longest life occurred where
sprocket diameters were larger than calculated for a perfect fit, as
judged from static measurements of film and sprocket dimensions.
It was decided to investigate this observation further. The pro-
jector with which the work was done had been in use for some time
in wear studies and conditions of use had been chosen to tear the
film to pieces rapidly. No changes were introduced when the test

Oct., 1943] THE PROJECTION LIFE OF FILM 299

was started, but a recheck showed that the gate tension was heavier
than normal and might have caused too great a pull and elongation
of the film. Therefore, a second series was run alter the gate tension
was reduced, with the results shown in Table II.

TABLE u

"Normal" Gate Tension

Projections with Sprocket
Film Base Film Pitch No. 1 No. 2 No. 3 No. 4

Nitrate— Sample 1 0.1869 1215 1250 2350 1935

Nitrate— Sample 2 0.1867 810 1575 2439 2340

Safety— Sample 1 0.1869 205 545 450 445

Safety— Sample 2 0.1866 679 1263 1386 1390

This table shows a considerable increase in projection life over
the previous conditibns, but, surprisingly, it shows no reduction on
the average in sprocket diameter for maximum projections.

Such effects are difficult to explain. In the first series the in-
dication of a maximum is so definite, at a sprocket pitch greater
than that of the static film dimensions, that a general drop in the
sprocket pitch for maximum life was anticipated with a reduced gate
tension. Table II does not show any such drop.

However, the favorable showing on projection life is seen to be
definite regardless of an explanation of these details of the data.

A study of the worn perforations of the film showed different,
typical tears, depending on the relative pitch of film and sprocket
during the test. When the sprocket is small in comparison with
the film pitch, the entering tooth rubs the sprocket-hole, tending
to break or tear it with a push toward the surface of the film and
away from the sprocket itself. Conversely, when the sprocket is
large in comparison with the film, the film drags on the tooth as it
withdraws from the film tending to break or tear it by a pull toward
the film surface next to the sprocket. In the case of the best fit no
predominant tear could be found; in fact, many perforations had a
notch worn in them the width of a sprocket tooth and a few thou-
sandths of an inch deep.

The results of the tests emphasize the fact that small differences
of pitch can be important in determining limits of projection life,
and they suggest that much greater projection life is possible than
is usually achieved under theater and exchange conditions.

SOME CHARACTERISTICS OF AMMONIUM THIOSULFATE

FIXING BATHS*

DONALD B. ALNUTT**

Summary. — A brief description of the history and nature of ammonium thiosulfate
is given. Several practical formulas employing this agent are presented and their
advantages discussed. Some of the differences in characteristics between the am-
monium thiosulfate and sodium thiosulfate fixing baths are pointed out.

An explanation is offered to account for the apparent discrepancies in the effects of
concentration on clearing time reported by previous investigators. The speed of
fixation of ammonium thiosulfate is shown to be greater than sodium or lithium thio-
sulfates and greater than mixtures of ammonium chloride and sodium thiosulfate.

HISTORICAL

The author is indebted to J. S. Mertle,1 Technical Director, In-
ternational Photo-Engravers Union, for the following brief account
of the discovery and early application of ammonium thiosulfate to
the photographic process.

The fact that ammonium thiosulfate will dissolve silver halides
was established long before the development of the photographic
process as it is known today. Sir John F. W. Herschel is credited
with the discovery of the solvent action of the thiosulfates on silver
chloride. His paper,2 published in 1819, mentioned ammonium
thiosulfate as one of the thiosulfates which exerts solvent action on
silver chloride. This is probably the earliest mention of the use
of ammonium thiosulfate for this purpose. The first specific men-
tion of the increased rate of fixing of sodium thiosulfate in the presence
of ammonia or ammonium carbonate was made in 1866 by John
Spiller,3 who, two years later,4 recommended it as a fixing agent be-
cause its greater solubility in water induced its quicker elimination
from plates and papers during washing after fixation. Practically
the same idea was voiced in 1892 by Labarre5 who pointed out the
easy solubility of ammonium thiosulfate and its more rapid action
as compared to an equally concentrated solution of the sodium
derivative.

* Presented at the 1942 Fall Meeting at New York.
** Research Laboratories, Mallinckrodt Chemical Works, St. Louis, Mo.
300

AMMONIUM THIOSULFATE FIXING BATHS 301

Eduard Valenta6 in 1895 investigated the fixing action of am-
monium thiosulfate. He could see no advantage in its use, but
qualified his opinion with the statement that commercial samples
of the salt, at that time, seldom were free from contamination. In
spite of Valenta's verdict, Eduard Liesegang7 maintained his own
faith in the superiority of the ammonium compound. His method
of preparing the salt involved the reaction of sodium thiosulfate
solution with barium chloride, followed by treatment of the precipi-
tate with ammonium carbonate.

In 1906, the Viennese, Karl Seib, introduced a commercial prepara-
tion, "Rapid-Fixage," which was not a true ammonium thiosulfate,
but was converted to this state by admixture in water with am-
monium carbonate. The same year the German trust, Agfa,8
introduced a commercial fixing salt of ammonium thiosulfate con-
stituency under the name "Agfa-Rapid Fixing Salt" (Agfa-Schnell-
fixiersalz); it was patented in Britain (No. 25,869) in 1906.

Apparently ammonium thiosulfate has not heretofore been avail-
able in this country on a commercial scale in the purity required for
photographic use. It is now being offered as a stable 60 per cent
solution and as a stable anhydrous crystalline solid.

CHEMICAL NATURE

Chemically, ammonium thiosulfate is similar to sodium thiosulfate,
Na2S2O3 • 5H2O, except that the sodium is replaced by the ammonium
radical to give the molecular formula (NH4)2S2O3. Ammonium
thiosulfate crystallizes without water of crystallization in colorless,
glistening plates or sword-shaped monoclinic crystals. Its molecular
weight is 148 compared with 248 for sodium thiosulfate crystals.
Thus six parts of anhydrous ammonium thiosulfate will take the
place of ten parts of sodium thiosulfate crystals in any given chemical
reaction.

Ammonium thiosulfate reacts chemically in much the same way
as the other soluble thiosulfates. It is readily decomposed by
heating, and its solutions sulfurize readily when acidified in the
absence of sulfite. It has a strong solvent action for silver, mer-
curous and thallous chlorides, bromides, and iodides.

All of the soluble thiosulfates appear to have varying degrees of
solvent action on silver salts. Although the precise chemical reac-
tions involved. in the formation of soluble silver compounds from

302 D. B. ALNUTT [J. S. M. P. E.

insoluble silver halides are still obscure,9' 10 the reactions are gener-
ally indicated10- n as occurring in several steps as follows:

2AgBr + Na2S203 - > 2NaBr + Ag2S2O3 CO

Ag2S203 + Na2S203 - > Ag2Na2(S203)2 (2)

Ag2Na2(S203)2 + Na2S203 — > A&Na«(SiO,), (5)

As can be seen, each succeeding complex formed contains a higher
ratio of sodium to silver so that the complex formed in eq. 3 is the
highly soluble disodium-silver thiosulfate. The solubilities of these
complexes vary in inverse ratio to their silver content.

According to Klempt, Brodkorb, and Erlbach,12 the concentration
and density of saturated solutions of (NH4) 28203 at various tempera-
tures are as follows :

TABLE I

Per Cent by Weight and Density of Saturated Solutions of (NH^S^ at Various

Temperatures

Temperature, °C Per Cent Density

-10 (14°F) 60.3 1.322

0 (32°F) 61.6 1.332

20 (68°F) 64.5 1.342

40 (104°F) 67.2 1.347

60 (140°F) 69.4 1.351

A 60 per cent solution of ammonium thiosulfate is near the satura-
tion point and may deposit crystals in extremely cold weather. For
this reason, it is impractical to handle solutions of greater strength.

The relation between the concentration and specific gravity of
aqueous solutions of ammonium thiosulfate at 25 °G (77 °F) is shown
in Fig. 1.

The following table gives the data on which the curve in Fig. 1 is
based :

TABLE n

Concentration and Specific Gravity of Ammonium Thiosulfate Solutions at

25° C (77 °F)

Concentration in Per Cent by Weight Specific Gravity at 25°C

4.35 1.0200

9.23 1.0454

14.58 1.0743

19.32 1.1000

29.07 1.1598

38.84 1.2076

53.39 1.2641

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS

303

CHARACTERISTICS

The time of clearing, and consequently the time of fixation of an
ammonium thiosulfate fixing bath, is approximately one-fourth that
of the common sodium thiosulfate fixing baths.

Fixing baths made with ammonium thiosulfate appear to retain
their hardening action over a wider range of pH than the sodium
thiosulfate baths. The commonly used hypo-fixing baths appear
to lose their hardening action when the £H has been raised to be-
tween 5.5 and 5.8, although their fixing power still may be good;
but, an ammonium thiosulfate aluminum salt bath will retain satis-
factory hardening action up to a pH of 6.5 to 7. This characteristic

1.300

5 1.200

ac
o

- 1. 100
It,

1.000

10 20 30 40 50

PERCENT BY WEIGHT (NH4)2S203

FIG. 1.

is a definite advantage, since it means that an ammonium thio-
sulfate fixing bath will harden satisfactorily more film than will a
similar sodium thiosulfate bath.

Concentrated fixing baths requiring only dilution for use can be
readily prepared with ammonium thiosulfate. This is due not
only to the slightly greater solubility of ammonium thiosulfate, but
to the fact that equal or greater efficiency can be obtained from the
lower concentration of ammonium thiosulfate. Thus, formula
ATF-1, which follows, can be prepared as a concentrated solution
in only 25 per cent of its final volume, whereas a comparable hypo
bath would require 40 per cent of its final volume for a concentrated

304 D. B. ALNUTT [j. s. M. P. E.

solution in which all the ingredients would be maintained in com-
plete solution.

Little difference is observed in the clarity of films just after fixa-
tion in either ammonium or sodium thiosulfate fixing baths. How-
ever, films fixed in ammonium thiosulfate solutions of greater than
normal concentration were clearer just after fixation than those
fixed in similar concentrations of sodium thiosulfate. This is es-
pecially true of x-ray films.

It is generally known that prolonged treatment of a photographic
image in an acid-hardening fixing bath will reduce the density of the
silver deposit. Experiments designed to compare the reducing
action of ammonium thiosulfate and sodium thiosulfate fixing baths,
both fresh and used, indicate that the reducing action of ammonium
thiosulfate is no greater than that of sodium thiosulfate, except for
papers and process film.

The recently published F-7 formula of Crabtree et a/.,13 using
ammonium chloride to give greater fixing speed, was compared with
ammonium thiosulfate fixing baths, both as to speed and hardening
properties. It was found that ammonium chloride additions to
regular sodium thiosulfate fixing baths increased their speed con-
siderably, but that these baths were still slower in their fixing action
than straight ammonium thiosulfate baths. Furthermore, am-
monium chloride seems to decrease the hardening action of such
baths.

It was thought that the greater solubility of ammonium thio-
sulfate might increase the ease of washing it out of emulsions. How-
ever, washing experiments indicate that this agent is eliminated at
about the same rate as sodium thiosulfate.

FORMULATION

The modern acid-hardening fixing bath is expected to perform
other functions besides transforming silver halides into soluble salts.
Some of these other functions are: hardening the emulsion, stopping
development, and preventing stains. In order to accomplish these
results satisfactorily, an acid-hardening fixing bath should have
certain qualities. Crabtree and Hartt14 enumerate six important
requirements for a satisfactory acid-hardening fixing bath which,
briefly summarized, are as follows:

(1) It should fix with sufficient rapidity

(2) It should not sulfurize.

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 305

(5) It should not form a sludge.

(4} It should not cause blisters on film .

(5) It should produce sufficient hardening.

(6) It should have a satisfactory service life.

In devising formulas using ammonium thiosulfate, our aim was
to produce fixing baths which would retain all of the speed of fixing
possessed by simple solutions of the agent; which would have no
deleterious effect on the photographic emulsion; and also would
have sufficient hardening action. Other requirements, such as
stability of the solutions, service life of the bath, etc., were con-
sidered of secondary importance.

Baths were first formulated using ammonium compounds through-
out; that is, ammonium tliiosulfate, ammonium sulfite, and am-
monium alum. Such baths were found to have no advantages over
baths made with ammonium thiosulfate, sodium sulfite, and potas-
sium alum. In fact, the speed of fixation was found to be influenced
almost entirely by the concentration of the ammonium thiosulfate
used in the formulation of the bath. For this reason the formulas
devised and tested were based largely on known satisfactory formulas
by substituting ammonium thiosulfate for sodium thiosulfate in
varying proportions.

Ammonium Thiosulfate General Purpose Acid-Hardening Fixing
Bath. — This bath contains approximately 150 grams of anhydrous
ammonium thiosulfate per liter. At the time this concentration
was chosen, it was believed that this strength produced the most
rapid fixing action, although later it was learned that the speed of
fixation increased as the concentration was increased up to a satu-
rated solution. The amount of sodium sulfite was chosen to conform,
in general, to concentrations used in known satisfactory fixing
baths. The amount of boric acid was chosen for the same reason,
since baths using this concentration are known to inhibit satis-
factorily the precipitation of an aluminum sulfite sludge.

In sodium thiosulfate baths, aluminum chloride is said to have
several advantages over alum,15 the most important of which is its
increase in the sludging and sulfurization life of the bath. It was
found experimentally that aluminum chloride was a satisfactory
hardening agent in ammonium thiosulfate baths. The amount of
acetic acid was determined by empirical methods so that the pH
produced was in the known critical range for the proper functioning
of the aluminum as the hardening agent. The selection of aluminum

306 D. B. ALNUTT [J. S. M. P. E.

chloride as the hardening agent made it possible to use this formula
as a concentrated ready-to-use, two-solution fixing bath. The
A TF-1 formula is given both in the ready-to-use form and in a con-
centrated solution form suitable for liquid packaging.

ATF-l

Ammonium Thiosulfate General Purpose Acid-Hardening Fixing Bath

One Liter
Ingredients Ready-to-Use Concentrated

Water 700 cc

Ammonium thiosulfate, 60 per cent solution 185 cc 185 cc

Sodium sulfite, anhydrous 12 gm 12 gm

Acetic acid, glacial 9 cc 9 cc

Boric acid 7 . 5 gm 7 . 5 gm

Water, enough to make 250 cc

Aluminum chloride hexahydrate 12. 5 gm 12. 5 gm

Water, enough to make 1000 cc 25 cc

Dissolve the chemicals in the order given. Add the acetic acid slowly
while stirring. Dissolve the boric acid in a small amount of hot water
before adding it. When making the concentrated formula, keep the
aluminum chloride solution separate until ready to make up the bath.
To prepare a ready-to-use fixing bath, the concentrated solution should
be diluted with 750 cc of water and the aluminum chloride solution added
slowly while stirring.

The A TF-1 formula has been found to have good service life, ex-
cellent hardening action, and rapid clearing action. When made up
in concentrated form, the solutions are remarkably stable. Because
of this latter property, this bath is well suited for x-ray work.

Ammonium Thiosulfate-Chrome Alum Acid-Hardening Fixing
Bath. — Formula A TF-2 was developed to produce a fixing bath whose
hardening action could keep pace with its fixing action. It is well

ATF-2

Ammonium Thiosulfate-Chrome Alum Acid-Hardening Fixing Bath

Ingredients One Liter

Water 700 cc

Ammonium thiosulfate, 60 per cent solution 185 cc

Sodium sulfite, anhydrous 15 gm

Sulfuric acid, 5 per cent 80 cc

Potassium chrome alum 15 gm

Water, enough to make 1000 cc

Dissolve the chemicals in the order given. To make sulfuric acid
5 per cent, add 5 cc of C. P. acid to 95 cc of cold water slowly with
rapid agitation.

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 307

known that chrome alum gives not only extreme hardening of gelatin
emulsions, but that this action is relatively rapid when it is used in a
bath whose acidity is properly adjusted.

This bath produced satisfactory hardening within the time neces-
sary for it to clear most types of emulsions. In common with most
chrome alum acid-hardening fixing baths, the service life of this
bath is short and it has poor keeping qualities.

Ammonium Thiosulf ate- Chrome Alum Acid-Hardening Fixing
Bath (Suitable for Dry Packaging) . — Since the rapid hardening, rapid
clearing type of fixing bath would be useful largely in military opera-
tions, race tracks, news work, etc., it was considered desirable to
create a formula of this type that could be packaged as dry chemicals
to facilitate the distribution of such a fixing bath. Formula A TF-3,
which follows, takes advantage of the strong acidic properties of the
stable, solid sulfamic acid16'17 to produce a fixing bath having essen-
tially the same properties as ATF-2. It was also found necessary
to use a slightly dehydrated form of potassium chrome alum, dried
to about 85 per cent of its original weight, to give a mixture of acidic
ingredients that would not cake in the package. The amount of
ammonium thiosulfate was also increased in this bath to take ad-
vantage of the slight but important decrease in clearing time which
this concentration would produce.

ATF-3

Ammonium Thiosulf ate- Chrome Alum Acid-Hardening Fixing Bath (Suitable for

Dry Packaging)

Ingredients One Liter

Ammonium thiosulfate, anhydrous 200 gm

Sodium sulfite, anhydrous 15 gm

Potassium chrome alum (dried) 13 gm

Sulfamic acid 9 gm

(To make potassium chrome alum (dried), dry the regular
chrome alum slowly to drive off about 15 per cent of its original
weight.)

Mix the ammonium thiosulfate and the sodium sulfite and
package in a large container. Mix the alum and the acid and
package in a small separate container. For use, dissolve the
ingredients of the large container in approximately 700 cc of
water. Dissolve the acidic ingredients from the smaller con-
tainer in about 100 cc of water and add this solution to the
former slowly while stirring. Make up the final volume to
1000 cc.

308 D. B. ALNUTT [J. S. M. P. E.

Fixing baths made from powders compounded according to the
ATF-3 formula behave very similarly to the ATF-2 fixing bath.
The powders themselves have proved to be reasonably stable over a
storage period of four months except that the solid ammonium thio-
sulfate has a tendency to cake slightly. This tendency has not been
found to be detrimental to the use of this type of package.

Ammonium Thiosulfate General Purpose Acid-Hardening Fixing
Bath (Suitable for Dry Packaging}. — A formula consisting entirely
of solid ingredients that would give a bath similar in properties to
the A TF-1 fixing bath was also developed. In this project, we were
guided by the recent work of Woosley and Pankhurst18 who made
use of the combination of sodium acetate and sodium bisulfate to
produce the necessary acidity in their fixing baths. These authors
used equal weights of acetate and bisulfate. We found that a ratio
of bisulfate to anhydrous acetate of three to two gave a bath of
proper £H for satisfactory functioning of the hardening agent.

ATF-4

Ammonium Thiosulfate General Purpose Acid-Hardening Fixing Bath (Suitable for

Dry Packaging)
Ingredients One Liter

Ammonium thiosulfate, anhydrous 150 gm

Sodium sulfite, anhydrous 15 gm

Sodium acetate, anhydrous 21 gm

Boric acid 10 gm

Sodium bisulfate 31 gm

Potassium alum 15 gm

Package the ammonium thiosulfate and sodium sulfite in a
large container. Make a separate moisture-proof packet of the
sodium acetate and place it in the large package. Mix the
boric acid, sodium bisulfate, and potassium alum and package
in a small container. To make up the solution, dissolve the
contents of the large package in about 700 cc of water and add
the sodium acetate from the small packet. Dissolve the con-
tents of the smaller package in about 200 cc of warm water
Add the second solution to the first slowly while stirring.

Exhaustion tests on this bath indicate that it has good service life,
produces satisfactory hardening, and has satisfactory capacity for
carried-over developer. Keeping tests have not been completed
on the dry packaged chemicals, but after two months they appear
to be stable.

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 309

Ammonium Thiosulfate General Purpose Acid-Hardening Fixing
Bath. — Since aluminum chloride hexahydrate is not a common
photographic chemical, a fixing bath having characteristics similar
to the A TF-1 was developed, using the regular photo grade of potas-
sium alum. It was also found that by increasing the amount of the
ammonium thiosulfate to 200 grams per liter a considerable exten-
sion of the service life of the bath could be obtained. Furthermore,
the solid ammonium thiosulfate was designated in this foimula,
since this type of material is more adaptable to commercial handling.
The A TF-5 formula, which follows, incorporates these modifications.

ATF-5

Ammonium Thiosulfate General Purpose Acid-Hardening Fixing Bath

Ingredients One Liter

Water 700 cc

Ammonium thiosulfate, anhydrous 200 gm

Sodium sulfite 15 gm

Acetic acid, 28 per cent 55 cc

Boric acid 7.5gm

Potassium alum 15 gm

Water, enough to make 1000 cc

Dissolve the chemicals in the order given. Dissolve the boric
acid in a small amount of hot water and add it to the bulk of the
solution.

This bath was found to have an exceptionally long service life,
and it produced satisfactory hardening over a long period of time.
All of its ingredients, except the ammonium thiosulfate, are regularly
available in any photographic laboratory.

A more complete description of the properties of these formulas
will be given in the experimental section that follows. It is believed
that ammonium thiosulfate can be used to advantage not only in
the general type of fixing bath, but also in formulas designed for
special types of work, such as non-hardening fixing baths and re-
plenishers for acid-hardening baths.

EXPERIMENTAL

Rate of Fixing. — The chief advantage of the ammonium thio-
sulfate fixing bath is the rapidity with which it fixes photographic
emulsions. In order to study the rate of fixation, a method of deter-
mining "clearing time" was first adopted. It is well known that the

310 D. B. ALNUTT [J. S. M. p. E.

clearing time is the time necessary for the turbidity of the silver salt
in the emulsion to disappear. Evidence has been produced to in-
dicate that the fixing time is synonymous with the clearing time.19- 20
However, Warwick21 showed that fixation should be continued for
twice the clearing time to be sure of removing all the unreduced
silver salts. It is a generally accepted safety measure to fix all
photographic emulsions for twice as long as it takes for them to
clear if permanence is desired.

Numerous experimenters have used various means of measuring
the clearing time of photographic emulsions. An adaptation of the
method of C. Welborne Piper22 seemed to give the most reproducible
results and it was used in these experiments. With the hope that
some day some such method may be standardized, a complete de-
scription of the method used in these experiments is given :

The fixing solution to be tested was placed in a shallow glass tray. A sheet of
matte-finish, black paper of sufficient size to cover the bottom of the tray was
immersed in the fixing solution to provide a black background (paper usually
packaged between sheets of cut film was found to be satisfactory for this purpose) .
A streak or puddle of the fixing solution to be tested was placed on the center of
the strip of film to be tested, using a glass rod, and the streak was allowed to re-
main on the film for approximately one-fourth of the expected clearing time.

When wet film was used, it was difficult to prevent the fixing solution from
running over the film, so an alternate method was used; such as immersing one
end of the strip or, better still, bending the strip in the form of a horseshoe and
immersing the center portion of the strip in the bath for approximately one-fourth
of the expected clearing time. Then, the entire strip of film was plunged into the
fixing solution and a stop watch was started simultaneously. The strip of film
was vigorously shaken when first immersed and was given two or three shakes at
ten-second intervals thereafter.

The best method of observing the disappearance of the turbidity of the emulsion
was to view the strip of film at a low angle using illumination placed directly above
the tray. It also helped to have a dark-colored background on the opposite side
of the dish from which the observation was made.

End of Clearing Time

(a) For combinations of films and solutions that produced completely trans-
parent emulsions, the clearing time was taken as that point at which the last
trace of turbidity disappeared. If traces of turbidity, which were patently caused
by finger marks or contamination, remained after the clear portion of the film
had become largely transparent, they were disregarded.

(b) For combinations of films and solutions that failed to give completely
transparent emulsions, the clearing time was taken as that point at which the
streak or blotch produced by the preliminary treatment with the solution became
indistinguishable from the remainder of the emulsion.

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS

311

The concentration of the fixing bath, the type of emulsion used,
the temperature of the fixing bath, and, to a slight extent, the in-
gredients used in the acid-hardening solution, all influence the rate of
clearing. The concentration of the fixing bath has the largest
single effect on the clearing time and will be considered first.

Conflicting views on the relationship between clearing time and
concentration of sodium thiosulfate have been reported. C. Wei-
borne Piper22 in 1913 concluded that there was an optimum con-
centration of sodium thiosulfate at which the clearing time was a
minimum. Above or below this concentration the clearing time
increased. When the data were plotted with the clearing time along

5 4

2 3

d 2
i

50 100 200 300 400 500 600
CONCENTRATION IN GRAMS PER LITER

FIG. 2.

700

the vertical axis and the concentration along the horizontal, a gener-
ally broad based, ^/-shaped curve resulted. The bottom of the U
was the point of most rapid clearing, and it occurred at a concentra-
tion of about 40 per cent sodium thiosulfate at 20 °C (68 °F). Crab-
tree and Hartt14 reached the same general conclusion in 1929. In
striking contrast to these findings, Hanson23 recently showed that the
clearing time progressively decreased with increases in the concen-
tration of sodium thiosulfate. He found no optimum concentration
at which clearing time was at a minimum and offered no explanation
of the apparent contradiction between his observations and those
of the earlier workers.

312

D. B. ALNUTT

[J. S. M. P. E.

We have now found that in the case of ammonium thiosulfate
either type of clearing time curve can be obtained, depending upon
whether the measurement is made on dry or wet film. Based on
our observations, our conclusion is that Piper, and Crabtree and
Hartt must have measured clearing time on dry film while Hanson
must have used wet film. When a dry emulsion is immersed in a
fixing solution, the solution must wet and diffuse into the emulsion
before chemical reaction can take place. Dry emulsions placed
directly in 40 per cent to 50 per cent sodium thiosulfate solutions do
not clear in an hour or more at room temperatures. Wet emulsions
similarly treated clear readily. That the more highly concentrated

14
13

ul 12
r> H

- 10

~ 8

50 100 200 300 400 500 600 700

CONCENTRATION IN GRAMS PER LITER

FIG. 3.

solutions do not diffuse into the dry emulsion as rapidly as the more
dilute solutions seems entirely reasonable.

In our work we measured the clearing time of wet film, since this
gives values of more practical photographic significance.

Fig. 2 shows the clearing times of Super-JOT film at various con-
centrations of both sodium and ammonium thiosulfates. The film
was soaked in distilled water for five minutes before each determina-
tion was made. The main curves show the clearing times of the two
agents at 25 °C (77 °F). Supplementary curves in broken lines show
the clearing times at 20 °C (68 °F) and 15°C (59 °F). Not only is the
time of clearing shorter at the higher temperatures, but it will be
noted that the retarding action of high concentrations is practically

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 313

absent at 25 °C (77 °F). The wide difference in speed between the
action of the sodium and the ammonium thiosulfate is apparent.
The time of clearing for the ammonium thiosulfate becomes rapidly
less as the concentration is increased up to about 20 per cent. There-
after, the increased speed is not commensurate with the extra quanti-
ties of the agent used. It is apparent that a solution of ammonium
thiosulfate containing 200 grams per liter is as rapid in its action as
that of a sodium thiosulfate solution containing 700 grams per liter.

Schramm24 has suggested that lithium thiosulfate might give even
more rapid clearing action than ammonium thiosulfate. Clearing
times were run on solutions of different strengths of lithium thio-
sulfate, in the same manner as those illustrated in Fig. 2. Fig. 3
shows the clearing times at 20 °C (68 °F) of Super-JO" film at various
concentrations for all three thiosulfates. As can be seen, the clear-
ing times of lithium thiosulfate fall between those of the sodium and
the ammonium thiosulfates. It is interesting to note that the re-
tarding effect of higher concentrations of lithium thiosulfate on the
clearing times is much more pronounced than it is with ammonium
thiosulfate.

Experimental determinations of clearing times at widely variant
temperatures indicate that temperature is also an important factor
affecting the clearing time. An idea of this effect may be had from
the fact that a 15 per cent solution of ammonium thiosulfate re-
quires two and one-quarter minutes to clear Super-X^T film at 10°C
(50 °F), but at 60 °C (140°F) this same solution clears the emulsion
in fifteen seconds.

Various types of emulsions require different fixing times, as in-
dicated by Table III below. The clearing times are given in seconds
for a solution of ammonium thiosulfate containing 148 grams per
1000 cc, as compared to a solution of sodium thiosulfate containing
248 grams of the crystalline solid per 1000 cc.

TABLE ni
Clearing Time in Seconds of Various Emulsions at 20° C (68° F)

Type of Film (NH4)2S2O» NajSzO.-

Process 13 21

X-ray 35 96

Fast Fine-Grain 50 215

Super-Fast Panchromatic 52 210

Standard Panchromatic 58 238

Orthochromatic 60 240

314 D. B. ALNUTT [j.S. M. P.E.

These two concentrations of the thiosulfates are chemically
equivalent. It will be noted that the ammonium thiosulfate clears
the film in from one-half to one-quarter the time required by the
sodium thiosulfate solution.

Another factor, which might possibly affect the clearing time of
emulsions, is the pre-treatment of the emulsion before it reaches the
fixing bath. In nearly every case this pre-treatment will include
development, which means exposure for a period of several minutes
to a solution of strong alkalinity and a rinse in a short stop bath with
or without a hardener. Experiments of Sheppard and Mees25 in-
dicated that formalin hardening had no effect on the rate of fixation
of photographic film. Experiments by Crabtree and Hartt14 indi-
cated that excessive quantities of the hardener constituents of a
stop bath absorbed into the emulsion would retard fixation. For
all practical purposes, when using normal hardening baths, the
hardener did not materially affect the time of fixation. One or two
simple tests confirmed these statements in our own experiments.

Extensive experiments showed that the amount of absorbed water
contained in the emulsion had a large effect on the clearing time.
This was especially true of concentrations of thiosulfate higher than
those ordinarily used. It did not appear to make any difference
whether the film was first soaked in a developer, a sodium carbonate
solution, or plain water, as long as the emulsion had been permitted
to absorb sufficient water. Experiments on the length of time
necessary for the Super- JOT emulsion to absorb sufficient water for
its clearing time to reach a minimum in any particular concentration
of thiosulfate, showed that at 20 °C (68 °F) the time was approxi-
mately three minutes. Therefore, in all clearing time tests, the
standard preliminary treatment was to soak the emulsion to be
tested in distilled water at 20°C (68°F) for at least five minutes.

Clarity of Fixed Emulsions. — It has been claimed by Dawson26
that ammonium thiosulfate fixing baths produce a completely trans-
parent image as soon as the film is cleared, whereas sodium thio-
sulfate fixing baths ordinarily leave a haze in the image until the film
has been completely washed. We found that #-ray films fixed in
ammonium thiosulfate solutions containing 200 grams per liter were
clearer than those fixed in sodium thiosulfate solutions of this con-
centration. Below this concentration the differences in clarity were
not significant. At concentrations greater than 200 grams per liter,
the difference in clarity was more pronounced. When this experi-

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 315

ment was repeated, using Super-XJT film, little or no difference in
clarity could be noticed between the ammonium and sodium thio-
sulfate solutions until a concentration of 260 grams per liter was
reached. Dawson's claim was substantiated in the case of x-ray
films, but a comparable difference does not seem to exist with Super-
XX film.

Reducing Action. — The fact that fresh fixing baths have a definite
reducing action on the silver image of a photographic emulsion has
been known for some time. Russell and Crabtree27 in 1932 studied
the reducing action of fresh fixing baths on the silver image of a
photographic emulsion. They concluded that the amount of re-
duction produced by a given fixing bath was directly proportional
to its acidity. Therefore, when using fresh chrome alum baths
having high acidity, the amount of reduction became important.
However, in ordinary work, except with very fresh potassium alum
baths, this reducing action was insignificant. Dawson26 has pointed
out that the reducing action of ammonium thiosulfate fixing baths
at equal />H values was definitely greater than those of sodium
thiosulfate fixing baths on x-ray film. It also has been reported
by J. S. Mertle1 that experiments with process plates used in lithog-
raphy have definitely showed that the opacity of the dots can be
lessened materially by prolonged treatment in the A TF-1 fixing bath.
Therefore, it is recommended that process films or plates should be
allowed to remain in ammonium thiosulfate fixing baths not longer
than double their clearing time.

Experiments with photographic papers have shown that the
fresh ammonium thiosulfate fixing baths can have a decided re-
ducing action on the images. Ammonium thiosulfate fixing bath
formulas, containing 150 grams per liter, appeared to give no notice-
able reduction in a 10-minute fixing period. However, formulas
using 200 grams per liter, such as ATF-4 andATF-5, have a marked
effect within eight minutes. Therefore, when fixing baths ATF-4
and 5 are used for photographic paper, it is recommended that the
prints should not be allowed to remain in the bath longer than four
minutes. The high acidity chrome alum formulas should not be
used for photographic paper.

Hardening Properties. — The most important property of any
fixing bath, besides its ability to fix emulsions properly without
deleterious effects, is its ability to produce satisfactory hardening
of the gelatin so that such emulsions may be washed and dried with-

316 D. B. ALNUTT [j. S. M. P. E.

out damage. Aluminum or chromium compounds have been most
generally used in acid-hardening fixing baths. An extensive dis-
cussion of the action of these two agents and of the theories con-
nected with their hardening action is given by Sheppard, Elliott,
and Sweet.10 Their work showed that the efficiency of the harden-
ing action of the alums was dependent almost entirely on the £H of
the solution in which they were used. It follows that the ability
of the fixing bath to maintain the proper acidity, even with con-
tinual additions of alkali carried over from the developer, is a matter
of prime importance in the production of serviceable fixing bath
formulas.

Measurement of the degree of hardening of any particular bath on
a gelatin emulsion is usually made by determining the melting point
of the treated emulsion. One of the oldest and most commonly used
methods of determining the melting points of gelatin emulsions is
described by Crab tree and Hartt.14 More recently, Woosley and
Pankhurst18 described a method of determining melting points
which appeared to us to have greater reproducibility. Instead of
determining the melting point or dispersal point of the gelatin emul-
sion simply by raising the temperature of a water bath in which it
was immersed, the emulsion was continually abraded by a slight
but fairly constant pressure from a rubber-tipped stirring rod.
The melting point determined by this method is defined as the lowest
temperature at which this stroking with the rubber-tipped glass rod
first produces detachment of the gelatin from the film base. Melt-
ing points determined by such a method are several degrees below
those determined by the older method, but they are probably more
in accordance with the requirements of practice.

In order to determine the effect of various periods of washing and
drying upon the melting point of the hardened emulsion, strips of
film developed and fixed in the same solutions, at the same time,
were given different periods of washing and were allowed to dry for
different periods of time. The results indicated that washing periods
of from fifteen minutes to 120 minutes and drying periods of from
zero to twenty-four hours had practically no effect on the melting
point of the gelatin emulsion. Therefore, in most cases, melting
point tests were run on film strips either immediately after washing
or after a short drying period. It is possible that films dried over a
considerable period of time may gain slightly in hardness, but our
experiments indicated that melting points run on freshly processed

Oct., 1943]

AMMONIUM THIOSULFATE FIXING BATHS

317

film and portions of the same film kept for several weeks were only
a few degrees different.

In Figs. 4 and 5, the ability of the A TF-1 and A TF-2 fixing baths

o 90

- 80

H
Z

O 70

5 60

5 50

2 4 6 8 10 12 14
c.c.oFMQ25/IOOc.c.ATF-l
FIG. 4.

o 90

24 6 8 10 12 14

c.c.opMQ 25/ 100 c.c. ATF-2

FIG. 5.

6 x
(L

to produce hardening when contaminated with varied amounts of
MQ25* developer is illustrated graphically. It will be noted that

*MQ25 Formula:
Metol

Sodium sulfite
Hydroquinone

1.25gm Sodium carbonate, anhyd. 25.00 gm

75 . 00 gm Potassium bromide 1 . 5 gm

4 . 75 gm Water, enough to make 1 liter

318

D. B. ALNUTT

[J. S. M. P. E.

the ATF-1 formula continues to produce satisfactory hardening
even after the £H of the bath has attained a value of over 6, whereas,
in common with other chrome alum fixing baths, the A TF-2 formula
rapidly loses its hardening action as the plrL approaches 5. The
inability of the unbuffered chrome alum bath to tolerate more than
a slight amount of developer contamination is also apparent.

In developing hardeners for ammonium thiosulfate fixing baths,
we considered it also desirable for the hardener to have rapid action
in order to take advantage of the rapid clearing action of these baths.

Fig. 6 illustrates graphically the speed with which a Super-XX
emulsion is hardened in the ATF-1 fixing bath and in the ATF-2
fixing bath. It is readily apparent that the chromium bath will

« 90

- 80

2 ?o

| 60

S 50

4 6 8 10 12
FIXING TIME IN MINUTES

FIG. 6.

give sufficient hardening for the proper handling of the film within
one minute, whereas it would probably be advisable, when using
the A TF-1 formula, to allow the film to remain in the bath from 2 to
4 minutes. In general, it appears that aluminum-hardening am-
monium thiosulfate fixing baths will give satisfactory hardening
within twice the clearing time.

Fig. 7 shows the effect of use on the rapidity of the hardening
action of the A TF-5 fixing bath. Super- JOT film is hardened more
rapidly in a used fixing bath having a />H of 5 than in a fresh bath.
This is occasioned by the fact that the optimum hardening action of
an aluminum alum fixing bath occurs in the range of 4.5 to 5.5 for
ammonium thiosulfate fixing baths, so that the rapidity of the action

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS

319

is not decreased until such a fixing bath is near its exhaustion point.
Since the fresh baths have a pH in the neighborhood of 4.2, optimum
hardening does not begin until use of the bath has increased its pH
to the effective hardening range.

The fact that addition of ammonium salts to sodium thiosulfate
fixing baths increases the speed of fixation has been long known.
C. Welborne Piper28 in 1914 found that a concentration of 4 per
cent ammonium chloride added to a 20 per cent sodium thiosulfate
fixing bath gave the optimum reduction in clearing time for the
Lumiere films he used. Recently, Crab tree, Muehler, and Russell13
published a rapid-fixing bath formula, designated F-7, using 50

o 90

? 80

0 70

z 60

2 50

I 23456789

FIXING TIME IN MINUTES

• FIG. 7.

grams of ammonium chloride and 360 grams of sodium thiosulfate
per liter. They also suggested the addition of ammonium chloride
to regular sodium thiosulfate fixing baths in amounts of 5 per cent
for the purpose of increasing the rapidity of action of such baths.
They pointed out, however, that additions of ammonium chloride
decreased slightly the hardening properties of such baths. There-
fore, in connection with the investigation of the hardening properties
of the ammonium thiosulfate fixing baths, it was thought worth while
to compare the hardening action of a typical ammonium thiosulfate
fixing bath with that of the F-7 fixing bath.

The curves in Fig. 8 represent the clearing times and melting
points of strips of Super-JOT film that had been developed in MQ-25

320

D. B. ALNUTT

[J. S. M. P. E.

for four minutes and then fixed for ten minutes each in a 50-cc sample
of the fixing bath tested. This procedure was the same as that used
in exhaustion tests, which will be explained in detail later. As
can be seen from the curves, the hardening properties of the A TF-1
fixing bath are considerably better than those of the F-7. It will
also be observed that clearing times of the F-7t although short, are
not so short as those of the ammonium thiosulf ate bath.

Blistering. — Blistering of film is a rather uncommon occurrence
when the more modern fixing bath formulas are used. The blister-
ing of emulsions is due to the rapid evolution of carbon dioxide gas
from the reaction of the sodium carbonate of the developer with the
acid of the fixing bath. If the processing temperature is main-

!: so

6 u

5 1

4 *
,1

I <->

246 8 10 12 14 16 18 20 22

NUMBER OF STRIPS

FIG. 8. '

tained at a normal level ; if the amount of carbonate in the developer
is not excessive ; and if the pH of the fixing bath in use is not too low,
this accidental blistering is very unlikely to occur. In all of our
testing of the five fixing baths, even at room temperatures of around
25 °C (77 °F) and while using the high carbonate D-19 developer,
blistering of the emulsion was never noticed.

Washing. — Extensive comparative experiments between an F-5
fixing bath and the A TF-5 fixing bath indicated that the thiosulf ate
was eliminated from films and papers at approximately the same
rate. These experiments were carried out by fixing a 4 X 5-inch
sheet of either film or paper in a small photographic tray for a ten-
minute period. The fixing bath was drained from the tray and the

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 321

sheet of material for thirty seconds and was replaced by a 100-cc
portion of distilled water. After thirty seconds of constant agita-
tion, this first wash water was discarded by draining the tray and
the material for thirty seconds. Then a second 100-cc portion of
distilled water was poured into the tray and, after a one-minute
period of constant agitation, this second wash water was drained
into a beaker and titrated with O.I N iodine solution. The third
wash water was put into the tray, given constant agitation for two
minutes, drained, and titrated. The fourth wash water was allowed
to act for four minutes; the fifth wash water for ninety minutes.
The last two wash waters were not given constant agitation, but the
tray was rocked every few minutes. Each wash water was titrated,
and the amount of 0.1 TV iodine consumed was used as a measure
of the amount of thiosulfate removed by each wash water. The
rate of removal of the two fixing agents was approximately the same.

Sulfurization. — The length of time a fixing bath can be stored with-
out precipitation of free sulfur is called its sulfurization life. Since
modern fixing baths sometimes have sulfurization lives of several
months, the usual practice14 is to store samples of the fixing bath to
be tested in glass-stoppered bottles at elevated temperatures. Due
to their high acidity, the chrome alum fixing baths ATF-2 and
ATF-3 sulfurize rapidly. Samples of ATF-4, ATF-5, F-5, and F-7
were stored, both at room temperature and at 40 °C (104°F), and
remained free from turbidity for four weeks. When similarly tested,
the ATF-1 fixing bath at 40°C (104 °F) showed a precipitate of free
sulfur in one week.

Sludging. — The property of a fixing bath to tolerate quantities of
alkaline developer without forming a sludge of aluminum sulfite is
called the "sludging propensity"; or sometimes, the "developer
toleration" of the fixing bath. Since in practice additions of de-
veloper to acid-hardening fixing baths are usually made at very
slow rates, the common method of carrying out this test has been
to add the developer slowly to the fixing bath while constantly stir-
ring, noting the amount of developer which first causes a slight
precipitate. Although this method has been used for some time,
Woosley and Pankhurst18 have described the method that we adopted
for one type of sludge test. Their definition of the relative sludge
life is "the number of cc of developer necessary to cause a perma-
nent opalescence when added to 100 cc of the fixing bath at a rate of
about one drop per two seconds while constantly stirring at 65 °F,"

322 D. B. ALNUTT [j. s. M. P. E.

The results obtained by applying this test to the fixing baths being
compared are set forth in Table IV.

TABLE rv

Relative Sludge Life at 20° C (68° F)

ATF-l ATP -4 ATF-5 F-5 F-7

Original pH 4.1 4.1 4.1 4.05 4.1

/>H at sludge point 7.1 8.1 7.9 7.8 7.7

cc MQ25 per 100 cc bath 80-85 150-200 150-175 150-180 140-175

With this type of test no sludging occurs even at 200 cc of MQ25
per 100 cc of bath for the chrome alum baths. It will be noted that
ATF-4 and ATF-5 compare very favorably with the F-5 and F-7
baths, whereas the A TF-1 bath has a lower relative sludge life.

Another method for measuring the relative sludge life of a fixing
bath has been used by Crabtree and Hartt,14 which consists in add-
ing various amounts of developer to equal portions of the fixing
baths to be compared and storing these samples at an elevated
temperature. The results of this type of test for sludging propensity
of the various fixing baths are given in Table V. These results are
expressed in the number of cc of MQ25 developer which were toler-
ated by 100 cc of a fixing bath at 40°C (104°F) for fifteen days
without the development of turbidity.

TABLE V

Relative Sludge Life at 40° C (104° F}

ATF-l ATF-4 ATF-5 F-5 F-7

cc of MQ25 per 100 cc bath 16 32 32 22 26

By this test for relative sludge life the chrome alum baths A TF-2
and ATF-3 failed in a matter of four days. In this length of time
a turbidity developed in the chrome alum baths whether the amount
of developer added was large or small. Here again, the ATF-4 and
ATF-5 baths compare favorably with F-5 and F-7, whereas the
A TF-1 bath has a slightly lower tolerance for carried-over developer.

Exhaustion Tests. — Many different methods have been proposed
for determining the exhaustion point of fixing baths. One of the
oldest and still commonly used axioms is, "Discard the fixing bath
when the clearing time of the film being processed becomes twice
as long as it was in the fresh fixing bath. ' ' Theoretical considerations
involved in determining the exhaustion point of a fixing bath were

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 323

published by Lumtere and Seyewetz29 in 1907. At that time,
through a study of the solubility of silver bromide in sodium thio-
sulfate, they proposed a test for recognizing the moment when a
fixing bath should be discarded. This test was the well known one
of exposing a drop of the fixing bath on a filter paper to strong light
and humid air. If this spot discolored, the fixing bath should be
discarded.

Another test of similar nature (depending on the amount of dis-
solved silver in the fixing bath) was attributed to Bayer by Clerk.30
This test consisted of adding 10 cc of a 4 per cent solution of po-
tassium bromide to 100 cc of the bath under test and noting the
formation of a permanent yellow precipitate which was assumed
to indicate exhaustion of the bath.

Lumiere and Seyewetz20 in 1924 revised their ideas on the ex-
haustion point of fixing baths and proposed another test that is
probably as practical as one can use for determining the presence
of silver salts in a finished emulsion. This test used a drop of sodium
sulfide solution (0.2 per cent) placed directly on the fixed and washed
emulsion under test. A discoloration of the emulsion connoted the
use of an exhausted fixing bath.

None of these tests is of practical value, however, if the fixing
bath loses its hardening properties before it has reached such a state
of exhaustion as to be discernible by them. Furthermore, in many
processing installations where machine processing is used, the in-
creased time of fixation becomes the limiting factor that determines
the useful life of the fixing bath.

Rather than depend upon any one or two methods of measuring
the exhaustion point of a fixing bath, our tests were designed to show
the melting point (hardening action), the clearing time, and the
change in pH of each bath during exhaustion. The spot tests on
filter paper were made on each bath, but are not shown in graphic
form. Experiments with the method of treating the fixed film with
sodium sulfide solution did not give conclusive evidence of the ex-
haustion point of the bath; so they were not continued throughout
the series.

Exhaustion tests, at best, are comparative only when done on a
very large scale and under practical working conditions. There-
fore, we do not feel that the results of the experimental exhaustion
tests can be applied directly to practical usage in determining the
amount of film that could be satisfactorily processed in any partic-

324

D. B. ALNUTT

[J. S. M. P. E.

ular fixing bath. The same process and technique were used on
each bath and every precaution was taken to make the tests com-
parative. The following is a brief outline of the method of running
the exhaustion tests :

Eight- by ten-inch sheets of Super-XX cut film were given a flash exposure
through a slit negative so that approximately 1/3 of the surface of the film was
exposed. This sheet was then cut into 1 X 8- inch strips having an exposed por-
tion in the center of each strip. Only 50 cc of the fixing bath to be tested was
used for each exhaustion test. Each strip was developed for four minutes in
MQ25 developer at 20°C (68°F). Then the strip was drained for five seconds
and immersed in the fixing bath at 20 °C (68°F) after having the spot of fixing

- 2

8 10 12 14 16
NUMBER OF STRIPS

FIG. 9.

20 22

solution applied to it, as described under clearing time tests. The clearing time
was noted and the strip was allowed to remain in the fixing bath for a total of
ten minutes in each case.

Then the strip was drained for five seconds and washed for thirty minutes in
water at 20°C (68°F). After washing, the melting point test, as described under
hardening properties, was applied to each strip. Strip after strip was processed
in the above manner using the same 50 cc of fixing bath until its />H indicated that
the bath was exhausted. At the beginning of the test and after every second strip
thereafter, a pH was run on the fixing bath. All pH measurements were made on
a Leeds and Northup Low Sodium Glass Electrode.

The results of the comparative exhaustion tests made on these
fixing baths are shown in graphs, Figs. 9, 10, and "11. As may be

Oct., 1943]

AMMONIUM THIOSULFATE FIXING BATHS

325

seen from Fig. 9, the F-5 is the only formula not showing rapid
clearing action. In each case the ammonium thiosulfate fixing baths
give somewhat more rapid fixation and continued to give this rapid
action longer than does the combination of sodium thiosulfate and
ammonium chloride. If the speed of fixation is used as the limiting
factor in the useful life of a fixing bath, it can be seen that A TF-5
should give the longest service life. ATF-1, ATF-4, and F-7 should
give practically equivalent service life and, of course, the chrome
alum baths, A TF-2 and A TF-3, would fail on other accounts.

Fig. 10 gives a general idea of the hardening properties of each of
these fixing baths during exhaustion. The chrome alum baths give

90
u

0 80

8 10 12 14 16
NUMBER OF STRIPS

FlG. 10.

20 22

excellent hardening for the first few strips, but rapidly lose their
hardening power, as their acidity is lost through neutralization
with carried-over alkali from the developer. The ATF-1 contain-
ing the aluminum chloride hardening agent gives much better
hardening action than any of the other baths. The ATF-4 and
AT F-5 give hardening action comparable to that obtained with the
F-5 formula. As will be noted, the hardening action of the am-
monium chloride F-7 formula is less than that of the other baths
tested.

Since the rate at which the developer was carried over into the
fixing bath was practically constant, and since the amount and type

326

D. B. ALNUTT

[J. S. M. P. E.

of acidity used in all the baths except the chrome alum baths were
the same, the pH of these baths during exhaustion would be expected
to rise at practically the same rate. As can be seen in Fig. 11, the
baths decreased in acidity at about the same rate. Naturally,
the lack of any buffering substance in the chrome alum baths gives
them a low tolerance for carried-over alkali and the />H of these two
baths increased more rapidly.

The spot test was made during the exhaustion of each of these
baths by placing one drop of the fixing bath on a piece of white
blotting paper after each strip was fixed. At the conclusion of the
tests, these spots were exposed to the direct rays of a mercury vapor

2 4 6 8 10 12 14 16 18 20 22
NUMBER OF STRIPS

FIG. 11.

lamp for a period of four hours. This exposure was found to be
sufficient to develop all the color that would eventually be developed
even by a prolonged exposure. By choosing the last spot that did
not develop color with this test, a comparison of the power of the
fixing bath for holding dissolved silver in a non-staining form can
be obtained.

The results of these spot tests were somewhat erratic and their
meaning is not entirely clear, since it is possible that fixing baths
containing enough silver to show stain by this test would still render
the silver salts in an emulsion sufficiently soluble to be completely
washed out. The apparently anomalous results of these tests are
shown as follows:

Oct., 1943] AMMONIUM THIOSULFATE FIXING BATHS 327

A TF-1 showed color after the 10th strip.
A TF-2 showed color after the 2nd strip.
A TF-3 showed no color after the 9th strip.
ATF-4 showed color after the 8th strip.
A TF-5 showed color after the 12th strip.

F-5 showed color after the 5th strip.

F-7 showed color after the 18th strip.

Although the service life of any given fixing bath depends largely
on the method used in determining its exhaustion point, it does
appear from these tests that any of the ammonium thiosulfate fixing
baths can be expected to give equal or better service life than com-
monly used sodium thiosulfate baths.

ACKNOWLEDGMENT

The author gratefully acknowledges the suggestions, advice, and
counsel of Dr. J. R. Ruhoff, and the assistance of other members of
the laboratory staff in this work.

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1 Private communication.

2 HERSCHEL, SIR JOHN F. W. : Brewster's Edinburgh Philosophical Journal
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3 SPILLER, JOHN: British Journal of Photography (June 15, 1866), p. 284.

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6 VALENTA, EDUARD: Jahrbuchfuer Photographic, 281 (1895).

7 LIESEGANG, EDUARD: Photographic Mosaics, 100 (1895).

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10 SHEPPARD, S, E., ELLIOTT, FELIX, A., AND SWEET, S. S.: "Chemistry of the
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11 NEBLETTE, C. B.: "Photography, Its Principles and Practice," Third Ed.,
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328 D. B. ALNUTT

18 WOOSLEY, D. P., AND PANKHURST, K. G. A.: "The Use of Sodium Hydrogen
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19 BULLOCK, E. R.: "On Convection Effects in Photographic Bathing Opera-
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21 WARWICK, A. W. : "The Laws of Fixation," Brit. J. Phot., 64 (1917), p. 617.

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28 HANSON, W. T., JR.: "The Fixing Process," Am. Phot., 36, No. 3 (March,
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24 SCHRAMM, WALTER: "The Chemistry and Practice of the Fixing Process,"
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26 SHEPPARD, S. E., AND MEES, C. E. K.: "Investigations on the Theory of
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28 DAWSON, G. A.: "Concentrated Solutions: A New Development in the
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27 RUSSELL, H. D. AND CRABTREE, J. I.: "Reducing Action of Fixing Baths on
the Silver Image," J. Soc. Mot. Pict. Eng., XVHI (1932), p. 371.

28 PIPER, C. WELBORNE: "Rapid Fixing Baths," Brit. J. Phot., 61 (1914), p.
193.

29 LUMIERE, A. AND L., AND SEYEWETZ, A.: "The Exhaustion Limits of Fixing
Baths," Z. Wiss. Phot., 5 (1907), p. 317.

30 CLERK, L. P.: "Photography, Theory and Practice," Pitman Publishing
Corp., New York (1937), p. 276.

THE MOTION PICTURE IN THE SERVICE OF THE ARMY

AIR FORCES*

LAWRENCE CARR**

In 1937 the Army Air Forces started its training film program.
Since that time millions of feet of film have passed through hundreds
of projectors and have been seen by hundreds of thousands of Air
Force soldiers from the lowest yard bird to the brassiest brass hat.

Our training film program is designed to provide, as quickly as pos-
sible, needed materials of instruction and, at the same time, to avoid
unnecessary duplication of similar materials being produced by the
Navy, the ground forces, the British, and other governmental agencies.

We have drawn upon the services of many specialists in the motion
picture industry to work closely with our specialists in the Air Forces.
By effecting such combinations of talents, it has been possible to
produce training films of outstanding instructional effectiveness.
Here I would like to pay tribute to the many individuals who have
given so generously of their professional skills and equipment in the
development of Army Air Forces training films. I know particularly
of the fine work done by Col. Keighley of the AAF, and Maj. Cowling
whom you all know. I believe he has been for some years an officer
of this organization.

It is General Arnold's wish that the training film program be inte-
grated with the instructional courses being given within the Air
Forces. Courses of study are analyzed to find subject matter that
can be presented to good advantage in motion picture form. Con-
tinuous contacts are maintained with instructors in this country and
abroad so that the training problems may be considered from the
standpoint of instructor and trainee.

There has existed a need for a central agency within the Army Air
Forces to coordinate the development of the training film program.
Recognition of this is one of the reasons why the Training Aids
Division of the Army Air Forces has been organized. Our offices will

* Presented at the 1943 Spring Meeting at New York.
** Colonel, Training Aids Division, Army Air Forces, Washington.

329

330 L. CARR [j. s. M. p. E.

be maintained at One Park Avenue, New York City, after May 20,
1943. The training film section of Training Aids is staffed with offi-
cers and enlisted personnel familiar with the motion picture industry.

Our problems with training films can be divided roughly into three
parts: they are concerned with production, distribution, and proper
utilization of films.

There are hundreds of films used in Air Forces instruction, cover-
ing such subjects as flight instruction, gunnery, bombardment, air-
craft detection and recognition, navigation, intelligence procedures,
and many other allied subjects, as well as films about engines, para-
chutes, brakes, instruments, photography, communication systems,
and inspection procedures.

There are more technical than tactical films due to the relative
stability of these subjects. With the changing or conflicting doctrines
of tactics, such film materials sometimes become obsolete before they
are completed.

General rules in deciding what films are to be produced are : first,
the relative importance of the subject to the training activities;
second, the suitability of the subject matter; and third, the produc-
tion requirements with reference to military personnel, materials,
and equipment.

After approval for production a study is made to determine what
elements of the sound motion picture should be employed to simplify
the concepts involved. Will it be animation to clarify abstractions or
complex movements, or will it be ultra-rapid photography to study
opaque objects and movements? Maybe photomicrography is
needed to reveal material stress and strain. Color is important, of
course, for medical and camouflage subjects.

Production units are maintained at Wright Field, Dayton, Ohio, for
the production of training films dealing with mechanical and elec-
trical equipment. Wright Field is the heart of the aeronautical re-
search activities of the Air Forces. Other facilities are at Culver City,
California, where the AAF first motion picture unit is located. This
organization has recently produced such films as Learn and Live,
Swim and Live, How to Fly the B-26, the film you will see upon the
completion of this talk, Straight and Level Flights and The Identifica-
tion of the Jap Zero.

Another important source of films is the aircraft equipment manu-
facturers. They prepare, through their own facilities and after co
ordination with training aids, films on the installation, operation, and
servicing of their equipment.

Oct., 1943] MOTION PICTURES AND ARMY AIR FORCE 331

After an Army Air Forces training film has been completed and has
the approval of qualified technical authorities, it is released for distri-
bution to Army Air Forces stations both at home and abroad. Distri-
bution needs are determined through the training sections of the
various Commands and Air Forces. A composite order is then given
to commercial laboratories for the needed number of prints. The
prints are sent directly from the laboratory to the using stations.
Sixteen-millimeter prints are used almost exclusively. At present, an
average of about 250 prints of each Army Air Forces training film is
distributed. At first thought, this number may seem great, but we
consider training films and reference materials similar to field manuals,
books, technical orders and other publications, and believe these
films should be available for use from local station libraries. If only
one trainee were to get one idea that would prevent one casualty or
destruction of one airplane, the cost of the film would be entirely
liquidated.

There are techniques for the use of training films as there are for
their production. We are preparing instructor's manuals for Air
Force films. These manuals include a detailed description of the
film, suggestions for its use, reading references, and objective test
questions.

The instructor can make or break the usefulness of a film. The
idea that large groups can be exposed to training films and come away
with a mastery of the content is erroneous, and it is one of the aims of
the Training Aids Division to point this out to users. Then, too, the
use of films unrelated to the instructional problem at hand is dis-
couraged; likewise, the showing of more than one film of ten or
fifteen minutes in any one period. Films requiring longer projection
periods are shown in short sequences. Particular attention must be
paid to the physical conditions under which films are shown. It is, of
course, deadly to show films immediately §after eating or in a room
inadequately darkened and ventilated.

In order that the same degree of supervision and coordination
which is realized in the preparation and production of training films
may be exercised in their use, especially trained officers are assigned
to help Army Air Forces stations obtain training film materials suited
to their particular needs.

We are firmly convinced that by carefully planning the production,
distribution, and use of training films, the value inherent in the pro-
gram can be made to contribute to the successful prosecution of the
war effort.

A COMPACT PRODUCTION UNIT FOR SPECIALIZED FILM*
O. W. HUNGERFORD**

Summary. — This paper outlines a few short cuts in the use of 16-mm film for
specialized film production with a minimum of personnel. Certain features of the
setup have reduced man-hours to a minimum and have made a compact, yet thoroughly
efficient, unit for the production of secret and timely subjects.

The war has brought about many changes and new ideas. Among
these was the overnight recognition of the sound motion picture
as an efficient medium for training and for presenting facts and data
in predigested form. While much has been written about the large-
scale training film production programs that are under way, little
has been said about the small, yet complete and self-contained pro-
duction units whose purpose it is to present facts and data in most
concise form. This paper will outline such a production unit.

For security and related reasons, it is usually essential that the
operating personnel of such units be kept at an absolute minimum,
yet the finished product must be one of highest technical quality.
From the standpoint of equipment, a requirement of this kind auto-
matically dictates 16-mm professional machinery; it also dictates
extreme versatility in the various persons needed to operate this
equipment. In such an organization it is not uncommon that each
person will be able to act as cameraman, sound recordist, film editor,
special-effects man, printer, and even projectionist as the need may
arise. In other words, the members of the staff are capable of
"doubling in brass." It is this ability together with the reliability,
simplicity, and precision of the machinery chosen that makes the
results possible.

CAMERA EQUIPMENT

The camera equipment includes a Maurer professional sound cam-
era for studio and general tripod work. This camera has pilot-pin

* Presented at the 1943 Spring Meeting at New York.
** Washington, D. C.
332

PRODUCTION UNIT FOR SPECIALIZED FILM 333

registration and has the pull-down claw located right at the base of
the picture aperture, eliminating that difficulty so common to the
magazine-chamber type of camera, frame line shift. This camera can
be wound back for double-exposure effect and for lap dissolve.

For studio work it is especially convenient that all lenses supplied
for it have been standardized at the SMPE standard distance be-
tween the image on the film surface and the mounting shoulder of the
lens. All three lens openings in the turret have been standardized
at this standard distance. Any standardized lens can be placed in
any lens hole. It will focus perfectly in all three. It is interesting
to note that as much as three to five thousandths of an inch has to be
taken off the lens shoulder to standardize the lens. This extra allow-
ance is left on the lens mount by the lens manufacturer because the
film in the usual loose-gate camera bellies away from the lens by
approximately this distance. We have also adapted this camera to
a stop-motion device for use on a title stand.

The animation stand is equipped with an Eastman Cine*-Special
camera adapted to animation by the installation of a calibrated
movement of the shutter so that accurate dissolves may be obtained
up to 64 frames. This camera is also equipped with a stop-motion
motor for either forward or reverse motion, and a direct frame-
reading counter that is reversible so that regardless of the direction
of travel of the film the counter may be read forward. We use this
camera on the technique known as "scratch-off" which we call our
"3-2 method." This is simply running the camera backward three
frames, then twice forward taking the picture on the second forward
motion. In this way we are always able to maintain the same frame
line. The effect stand for animation while quite simple is capable
of almost any type of action requiring little time in man-hours of
operation.

We have set up a standard for our Graphic Division for cell ani-
mation with two standard sizes of cells known as our A cell, which is
10 X 12V2 inches, and our B cell, which is 20 X 25 inches. These
cells are punched with a three-hole punch, the center hole being
L/4 inch round and the two side pins being ]/8 inch wide and ap-
proximately 1/2 inch long, spaced 4 inches from the center pin. This
size of punching has been adopted by the Navy Photo-Science
Laboratory as their standard and for convenience we have also
adopted it. A great deal of animation work is also carried on in the
old but very often forgotten technique of the cardboard cut-out

334 O. W. HUNGERFORD [J. S. M. P. E.

model and its counterpart. We have found that this type of pro-
cedure speeds up certain animation technique. Approximately 90
per cent of our work deals with animation, and almost 100 per
cent of our animation is shot on Kodachrome Type A using C. P.
bulbs for illumination.

SOUND EQUIPMENT

It is in this department that equipment flexibility and compactness
are evident. The basis of our 16-mm recording equipment is a
Maurer Model D Sound Recorder -with the usual noise-reduction
equipment. The amplification equipment is rack-mounted with
jumping-plug contacts for immediately locating any difficulty that
might arise in the equipment. The mixing equipment has an 8-
channel input with four active lines. These are permanently con-
tact-jumped from two microphone inputs and two turntable pick-ups.
The amplification equipment is set up for film recording, disk record-
ing or re-recording from either disk or film. The disk reproducing
equipment is designed to operate at either 33 or 78 rpm. The pick-
ups are Western Electric 9A which may be used for either hill-and-
dale or lateral recordings. The disk recorder is a Presto which is
suitable for either 33 or 78-rpm operation. The film -phonograph
equipment consists of two 35-mm film-phonographs and one Maurer
16-mm film-phonograph. This latter equipment has proved to be a
reliable and useful machine for many purposes other than re-record-
ing. Very often it is necessary to check the quality of commercially
produced prints. This is quite simple as the system has a consistent
and very low noise-level and the frequency characteristics of the
channel remain the same from day to day. Our projection equip-
ment consists of a Bell & Howell 750-watt projector that we have
rebuilt to hold a 1000-watt bulb, and in which we have installed a
special preamplifier so that its output may be fed directly into our
rack-amplifier for quality reproduction. We are now using a Jensen
coaxial wide-range loud-speaker for reproduction with this system.
At some later date we hope to install a good two-way reproducer for
this channel, such as a Jensen Type E. When one becomes accus-
tomed to a system of this sort the use of a conventional projector to
reproduce, for instance, a Kodachrome duplicate is rather a blow.
Such an arrangement as ours makes it very easy to discriminate be-
tween good and bad prints.

Oct., 1943] PRODUCTION UNIT FOR SPECIALIZED FILM 335

EDITING AND EDITING EQUIPMENT

Since most of the fact and data films are built to order, so to speak,
very little editing is necessary. Often the sound is made prior to the
actual shooting of animation. Therefore the animation action can
be accurately timed to the voice. In a composite picture in which
we use both live acting or clip shots with animation and occasionally
a live synchronized shot, the film is recorded after the assembly
process. Since these films are made with the intention of being
informative rather than entertaining or "arty," editing of them is
relatively a simple job. It must be so, for if the shots were com-
plicated by all sorts of angles, crosscuts, sound-effects, etc., this set-up
would defeat its purpose. If organizations of this kind were to think
of individualism, which might be called the niceties, of technical pro-
duction, we would be compelled to set the idea aside owing to the
unwarranted diversion of man-hours required for this type of "arty"
production.

In conclusion, let me leave this thought with you: while major
emphasis must be placed on the large training film project using a
great many specialists who need no skill beyond their own particular
field, small, compact, highly versatile production teams skilled in all
of the essential elements of production make up the personality of
these "facts-and-figures" units that are doing their bit very quietly in
this war. The nature of the material being portrayed in such films
must remain a military secret. Their importance, however, can not
be overlooked.

DISCUSSION OF INDUSTRY PROBLEMS*

ED KUYKENDALL**

I am delighted to be able to participate in the annual get-together
meeting of such able men who constitute the Society of Motion
Picture Engineers. You, gentlemen, are a most vital part of a great
industry, an industry that has made tremendous progress over a
period of years. You, who have contributed so much to the forward
movement of the motion picture industry, are to be congratulated
not only for your ability but for your complete determination to
move forward and better the all-round development of the motion
picture.

The Motion Picture Theatre Owners of America, which is the
largest and oldest trade association, has the same interests at heart
as you engineers — the development of the industry; that they
through their theaters can best and most intelligently serve the
public which, after all, is entitled to nothing less.

Over a period of years I have watched the growth and accomplish-
ments of your organization. You have gone forward every minute
of the time. The marks of your accomplishments are definitely
visible in and about the theaters in this good old U. S. A. You have
made it possible for us, the theater owners, to keep abreast of the
times — modern times, if you please. You have, in your eiforts, made
it possible for our theaters to be emblems of modern progressiveness,
and as the public, as well as theater management, walk into places of
amusement the results of your ingenuity and hard work can be seen
readily from all sides. It gives me great personal satisfaction to
realize that the theater owner is exploiting your brain child to the
fullest.

Still, the theater has a long way to go in progressive development;
so far to go yet that we are hesitant in looking down the road with
its many curves and bad crossings. But together, arm in arm, we

* Presented at the 1943 Spring Meeting at New York.
** President, Motion Picture Theatre Owners of America.
336

DISCUSSION OF INDUSTRY PROBLEMS 337

will continue the forward march of development and progress which
the public will surely recognize and show their appreciation at the
old box-office.

The all-out war in which we are now engaged has had its hard
touch on motion pictures. Many of us are not too happy with the
results of government regulation. Many of us will undoubtedly say
we would have done this and that differently. Many times I am
confused and wonder what it will lead to, but as I sit down and take
inventory of the general picture, it seems to me that we, as an in-
dustry, have suffered less than most other businesses.

The MPTOA was the first to emphasize the necessity of keeping
the theaters open during the stress of war, regardless of hardships
and regulations. This is our first duty to the public — we can accept
no other attitude. Motion picture entertainment is essential to the
levelness of our war-conscious minds.

In selling War Bonds, doing relief work, and conducting general
patriotic efforts, we put forth every possible effort, and the results
have been most gratifying. We are proud of this work, but it is no
more than we should do as good Americans. In fact, it is as little as
we should do. My slogan has been, "The most we can do, is the
least we should do." I am no believer in using what we have done
in our effort to get governmental consideration, but I am all out in
making every possible fight to get what justly belongs to us in this
confused and hurried world. It is my belief that we should fight to
the limit any attempt or thought to pass us by. We owe that to
those who have invested all they possess in our industry, and fight
we will for our rights — nothing more, nothing less.

Adapting theaters to wartime restrictions is a matter of vital im-
portance not only to theater owners, but to you of the Engineers.
In this day of priorities over almost everything, we can not continue
on the old basis, but must accept the all-out war theme and learn to
do without certain materials in this emergency. You of the En-
gineers, and we of the theater, must use our ingenuity to continue
operations of our theaters, maybe under restrictions, probably with
hardships, but do it we will. But, while we are doing this, we are
learning many things that will stay with us long after we have
knocked hell out of the Axis!

I can not put too much faith in the return of former employees.
In my mind, our industry will never be classified as essential to the
war effort, but we have not been declared non-essential. We are in

338 E. KUYKENDALL [J. S. M. P. E.

the twilight zone, and our industry is being judged now on a purely
individual basis. So it seems like wishful thinking to sit by and hope
that former, gifted employees will be sent back to us to resume im-
portant work before this fight to the death is over. So let us who
are still on the job work harder as individuals: improvise, create,
train women, use older men. We, as an industry, do not want to
do anything less than our full part in this war.

It is my opinion that the War Activities Committee should be given
every possible support by this entire industry. The MPTOA has
cooperated with this committee as individuals, and not as an organi-
zation. This precludes exhibitor politics. We, who have been
placed on this committee, are proud to serve with it, and we believe
that the War Activities Committee is the only one that could, and
has, functioned for the entire industry.

I have noted criticism from one source about too much flag waving
in the theaters. I go on record, personally, as not agreeing with this
thought. I believe it is our duty as an industry to see to it that
our beloved flag is waved in any and all places. It inspires confi-
dence, gives us a concrete encouragement: an emblem of the Ameri-
can way of life, may it ever wave, and may we, as an industry, leave
nothing undone to insure that its waving continues.

I like the name of your organization, "Engineers," meaning
planners, devisers, creators, progressive thinkers, carrying on for the
whole industry; and the engineers are vital parts of this war effort
outside this industry.

We will continue to have our industry worries. We will continue
to feel as an industry, and as individuals, that we are not getting our
just dues during the stress of war. But let's keep mindful of the
fact that it's because of war, and that we must keep ourselves more
on the alert to protect our fair interest. It means more work for all
of us, but that's no more than we can expect under present conditions.

There are many things, technically and otherwise, I could have
discussed with you. All are important and cover many of your
varied activities, but time prohibits and this is no place for a speech .

But if, in winning this war, we lose sight of the American principles
and way of life, we have gained very little, and would be very un-
happy after it was all over. So you and I, as Americans first, and an
industry afterward, have a big job before us which we accept with
the full importance of its meaning.

It is regrettable that there are quite a few among us who have

Oct., 1943] DISCUSSION OF INDUSTRY PROBLEMS 339

allowed the dollar mark to obscure their vision of the future and their
obligation to America. They are blinded by the collection of more
dollars, and are prone to allow themselves to see only the monetary
gains of immediate days. But I warn them : stormy days are ahead
for such minds; fairness will be forced on them whether they like it
or not. They may find that their immediate financial advantages
may be snatched away from them as there can be only one way for us
to conduct ourselves: fairness in our relations with each other and
patriotic and wholehearted effort for our government. It's the one
and only way you and I can hope to be happy and satisfied with our-
selves, and really enjoy, personally, what we are doing.

Let's you and I — all of us — keep our balance, continue to work
harder and harder for a continuance of our present way of life ; allow
nothing, or anything, or anybody, to change our course, that you, the
Society of Motion Picture Engineers, and we, The Motion Picture
Theatre Owners of America, can walk together down the highway of
life with the collective knowledge that we did our part, honestly, sin-
cerely, and can look the boys full in the face on their return, knowing
that we, too, have done our part as Americans.

SOME SUGGESTED STANDARDS FOR DIREC
16-MM PRODUCTION*

LLOYD THOMPSON**

Summary. — An increase in the use of direct 16-mm production makes it desirable
that certain standards be set up in order that all producers be able to follow definite
procedures. If such standards can be agreed upon it will make it much easier for the
producer to do his work and train his help. It will allow the equipment manufacturer
to produce better machines to handle 16-mm. It will allow the laboratories to give
better prints with a minimum of delay and a minimum of error. The standards that
are suggested should be studied closely by those interested and suggestions made.

The increased use of direct production of 16-mm film for both
sound and photography makes it highly desirable that certain stand-
ards be adopted covering the correct procedures to be used. As long
as only a few persons or companies were producing direct 16-mm films,
standards were not too important because procedures were used that
were found by experience to be satisfactory. However, when a large
number of persons or companies start using 16-mm film for commer-
cial exhibition, it becomes important that certain standards be adopted.
Unless this is done, it will be difficult to find technicians who are ca-
pable of working with different companies and almost impossible for
the producers to secure good laboratory service, and the equipment
manufacturers will be unable to build any sort of professional equip-
ment that will satisfy any great number of users.

Before any standards are adopted, however, it is necessary to find
out what is needed and what experience has shown will work. It is
always hard for a new industry to set standards because improve-
ments are constantly being made. Today's standard may be obso-
lete tomorrow. All of us can remember the beginning of radio and the
development that has since taken place. Today one might say that
the standards are set, but frequency modulation will probably demand
new standards. Therefore, any standards proposed in this paper

* Presented at the 1943 Spring Meeting at New York.
** The Calvin Co.. Kansas City, Mo.
340

DIRECT 16-MM PRODUCTION 341

should probably come under the name of Recommended Practices,
but there must be a beginning.

Direct 16-mm production, to be successful, depends upon good lab-
oratory service. There are several organizations with reputations
for doing good laboratory work, but even these concerns are not in
complete agreement as regards processing methods.

The problem of emulsion position has been previously discussed in
the JOURNAL1 and has been well covered. Two standards are being
used today: The emulsion may face either the light-source or the
lens. As far as picture position is concerned, one is as good as the
other, because the lens may be manually focused for either emulsion
position. However, sound is played often on a projector that does
not allow focusing of the sound-track, and this can result in a differ-
ence in sound quality depending upon the position of the emulsion
with respect to the lens. I say there can be a difference because most
persons will not be able to tell whether the sound-track is in or out of
focus as they listen to a large number of the prints being distributed
today. On a really good sound print there is a difference, but if the
sound-track is really good it will give satisfactory reproduction on an
average projector without the focusing arrangement.

Some producers and some editors produce pictures with large num-
bers of stock shots; this practice is likely to cause trouble if both
original reversal films and prints are used. The producer and editor
should familiarize themselves with the emulsion position and set
their own working standards. Recently I saw an original 16-mm
Kodachrome sent in for printing. The photography contained film
made on a silent stock and 16-mm sound stock, which is all right.
There were 16-mm sound leaders on both ends of the photography.
This was also all right, except that the leader on one end was spliced
with the sprocket-holes on one side and the other leader had the
sprocket-holes on the other side. The editor said he did not know
which side he was supposed to use so he used both sides !

The suggested recommended practice: when using the double system, shoot
the picture on stock perforated on both sides. Follow this procedure all the way
through. If stock shots are used, they should be on this type of stock if possible.
If sound stock must be used, be sure it can be printed. (A standard 16-mm
reduction sound-print can be cut into an original reversal film with emulsion
positions the same and should go through any of the printers being used today.)

Original pictures and sound-tracks coming into a laboratory for
printing are the most variable things imaginable. We have our own

342

L. THOMPSON

[J. S. M. P. E.

Oct., 1943] DIRECT 16-Mn PRODUCTION 343

standards for attaching leaders to original film for printing, and we
shall be glad to send them to anyone who is interested. We have had
some difficulty in getting people to follow them and have even been
told that they are not correct, but they have been checked a number
of times and we are certain of their validity. We have suggested that
identification and synchronizing marks be placed upon both ends of the
photograph and sound-track reels because all laboratories do not
print from the same end. Since 16-mm printers are not standardized,
this is probably the only procedure that can be recommended. Fig. 1
shows a suggested recommended practice.

The standard leader developed for 35-mm film is used by some pro-
ducers for their 16-mm originals. We are opposed to this practice
because in the field operators will often project the numbers on the
screen at the beginning of the picture. For good presentation plain,
marked leaders should be spliced to each new reel.

As a suggested recommended practice a leader four or five feet in length, such
as the reversal laboratories use on amateur reversal prints, is proposed.

If there is anything more unstandardized than leaders, it is the
light-change punch. We frequently receive originals having two or
three sets of light-change punches, and as a rule none of these will
work on our printers.

We have no suggested recommended practice for this. The only suggestion we
can offer is to set up some sort of standard, and in time most of the laboratories
will probably conform to it. It will also give printer manufacturers a basis upon
which to work.

While it is probably not the duty of the Society to set up standards
for the emulsions to be used for certain jobs, there are probably
many who are trying to do 16-mm production for the first time who
would welcome some sort of suggestions. Over a period of years we
have worked with many who were trying to make their own pictures,
and there have been times when they failed simply because they
used the wrong type of emulsion. We have found people trying to
shoot contrasty titles on blue-base negative stock instead of using a
high-contrast positive film.

While certain types of 16-mm film on the market can be developed
as either negative or reversal, most types of negative film will not
"reverse" successfully. Nevertheless certain persons still persist in
trying.

For several years the emulsion makers have been selling 16-mm

344 L. THOMPSON [j. s. M. p. E.

sound-recording film that is definitely superior to positive film, but a
few persons still try to use ordinary positive stock and others wonder
why their dupe negatives do not turn out well when they try to make
them on positive film.

In suggesting certain emulsions for specific purposes it should be
borne in mind that the list is subject to change. It is fairly standard
procedure for 16-mm producers to shoot their original photography
on either black-and-white reversal film or on color-film. (There are
some cases where color-film is used entirely, even when black-and-
white prints are wanted.) The following emulsions are suggested :

Black-and-White Photography

Original. — Standard-brand reversal film or color-film. The brand and type
must be decided upon by the individual. (For procedure see reference 2.}

Titles. — High-contrast positive film for cheap titles, but for professional titles
reversal film with the proper art work.

Work Prints. — Reversal prints on positive film, yellow-dyed sound-recording
stock (perforated on both sides), or reversal duplicating film. The positive film
is cheaper, and will usually serve the purpose.

Release Prints. — Reversal duplicates made on reversal duplicating film for first
prints, or for only a few prints. Dupe negatives should be used for a large number
of prints and should be made on panchromatic fine-grain duplicating negative.
Positive prints from duplicate negatives are best when made on fine-grain positive
film.

Color Photography

Original. — Standard-brand reversal color-film such as Kodachrome or Ansco
Color. Mazda-light type for Mazda lights, and daylight-type for daylight.
(Some prefer the Mazda type with filters for exteriors.)

Work Prints. — Same as for work-prints from original black-and-white photogra-
phy, unless the editor feels he must use color work-prints, in which case a regular
color release-print is made.

Release Prints. — (a) Color: Made on Kodachrome duplicating film, or equiva-
lent, (b) Black-and-white: Follow same procedure as with black-and-white
dupe negatives. If black-and-white reversal prints are wanted it is best to use a
duplicating film that is not color-blind, although it is more costly.

Sound

Original. — Use a 16-mm sound-recording emulsion made especially for the pur-
pose.

Prints of Sound Only. — Fine grained positive film.

We offer the above as recommended practice for correct 16-mm production,
and if the producer will follow these suggestions he can not go far wrong as 16-mm
production is done at the present time.

There have been a number of direct 16-mm productions made
where no work-print was used during the editing process, but as more

Oct., 1943] DIRECT 16-Mn PRODUCTION 345

persons become involved in the production of a picture, the more
necessary it becomes that the first editing be done with work-prints.
One serious difficulty in using 16-mm work-prints is that there has
been no standard method of edge-numbering originals and work-
prints so that the two can be easily matched.

For several years the Society has been discussing 16-mm edge-
numbering, and a Recommended Practice was finally set up. This
is all well and good, except for the fact that edge-numbered films are
available only on special order, and a number of emulsions are on the
market that must be used in direct 16-mm production that are not
available with edge-numbers under any condition.

Some time ago I recommended to the Society that all 16-mm re-
versal and sound-films be edge-numbered if the system were to work
out successfully for 16-mm production. However, because of certain
manufacturing difficulties it is not practicable to edge-number all
16-mm reversal film because there is no need for edge-numbering
most amateur films. For that reason I am now going to change my
recommendation. Since it seems to be impossible to get all 16-mm
producers to place special orders for edge-numbered film and use no
other kind of stock, it is recommended that

when work-prints are made of the originals, the original photography and work-
print be numbered by a machine as is done in 35-mm practice.

The work-prints can first be made, then the edge-numbers be put
on the work-print to synchronize with the edge-numbering on the
original developed photography. These numbers can be printed also
on the sound-track. The producer is thus relieved of the necessity
of using edge-numbered film for his originals. Unfortunately we
know of no one at the present time who can offer this service, but
we have investigated its possibilities and believed that before long
such a service will be offered.

There are many kinds of work-prints. Some have used regular
black-and-white reversal prints; others have had full-color prints
made from their color photography; and some work-prints have
been made as negatives after they have been printed on positive film.
Since most persons do not want to pay any more than is necessary for
work-prints, we have found that work-prints made on some cheap
emulsions such as ordinary positive film, and then reversed, give
very satisfactory results for most purposes. Work-prints from color-
film made in this way are also satisfactory.

346 L. THOMPSON [j. S. M. P. E.

We therefore suggest the following recommended practice: Black-and-white
work-prints from original black-and-white photography or color-film to be made
on positive film and reversal-processed where the minimum amount is to be spent.
If better-quality work-prints are desired, use regular reversal prints for black-and-
white or color or color-prints for color photography.

Many who are making direct 16-mm pictures for the first time do not
seem to realize the importance of securing the proper density for their
original sound-tracks or, if they do, they seem unable to give the
proper exposure to their film in order to realize this density. The
manufacturers of the film have, in most cases, suggested proper
densities for their film, but there are far too many cases where these
recommendations are not followed. This is something that can be
made a recommended practice, but each producer will have to work
out his own standards. Control of exposure for sound-tracks must be
critically and carefully checked.

There must be something extremely fascinating about the manu-
facture of 16-mm reels, because it seems as if every machine shop in
the country has put some sort of 16-mm reel on the market. After
examining some of these reels, we wonder whether some of the manu-
facturers ever saw a 16-mm reel before. A few years ago we thought
the 16-mm reel was pretty well standardized and would probably be
rather hard to change. However, so many changes have been made
during the past year or two that it is quite appropriate to suggest
standardization. The original 16-mm reel was made for amateur
use, and the idea of using a round hole on one side and a square hole
on the other side was to make sure the reel was placed properly on the
spindle. We have never yet seen a 16-mm professional who likes
reels of this type. Editors and cutters of 16-mm film find them es-
pecially bad. We have found them with all sorts of hub sizes, some of
which have been made so small that they will not work properly on
certain types of take-ups at the beginning of the film.

We suggest that 16-mm reels be standardized with square holes on both sides,
and that a certain hub diameter be chosen and adopted as standard.

Sixteen-mm editing equipment for the most part is made to handle
reels instead of cores, as is common in 35-mm practice. Nearly every-
one who has done much work with 16-mm uses these reels in editing,
and most 16-mm originals received in laboratories for printing come
in on reels. Furthermore, it is much safer and easier to handle film
on reels.

Oct., 1943] DIRECT 16-MM PRODUCTION 347

We suggest, therefore, that it be recommended practice to handle 16-mm film
on 16-mm reels.

We find that 16-mm film sent in for printing comes in all sorts of
lengths. Different laboratories are set up to handle different lengths —
some 100 feet, others 400 feet, up to 2000-ft rolls. This is all right
except there should be a stopping point somewhere, and some sort of
standard set for it. It is obviously impossible to get raw stock to
match the exact footage for every show, and this becomes somewhat
of a headache when sound is to be printed.

For a suggested recommended practice we suggest that original picture and
sound-track for 16-mm be edited into lengths of 390 feet so they may be printed
on standard length rolls of 400 feet. Leaders may bring the length up to 398 feet.

It probably does not make much difference in the final results, but
we feel that it might be a good idea to standardize the direction of
editing 16-mm film. Some persons edit from right to left and others
from left to right. This is partially a matter of taste and par-
tially a matter of equipment and the introduction of 16-mm sound-
tracks to the editing procedure. Certain equipment seems to work
better in one direction than in the other. Reels with square holes on
one side and round holes on the other call for editing in one direction,
and reels with square holes on both sides will allow the editor to work
in either direction. The splicer that is probably most commonly
used for 16-mm editing is the Junior Griswold with the 1/i6-inch splice.
When using this on original sound-film it is almost necessary to edit
from left to right. We have done so for years and have found a num-
ber of others who follow this procedure. All the equipment manu-
facturers do not agree and we suggest that some practice be recom-
mended in order that all editing equipment be in agreement.

Producers of 16-mm pictures should standardize their techniques
of performing certain operations and then adhere to their standards.
We have received commercial pictures for printing that contained
splices made on three or four different kinds of splicers. Such little
things can make a show look like the work of an amateur instead of
the work of a professional.

There is a great deal of work to be done in standardizing 16-mm
production methods. This paper has listed only a few of the problems.
It is hoped that other 16-mm producers will submit their suggestions
and that eventually some of the suggested recommended practices
will become standards.

348 L. THOMPSON [J. S. M. p. E

REFERENCES

1 OFFENHAUSER, W. H. : "A Review of the Question of 16-Mm Emulsion Posi-
tion," /. Soc. Mot. Pict. Eng., XXXIX (Aug., 1942), p. 123.

2 THOMPSON, L. : "Some Equipment Problems of the Direct 16-Mm Producer,"
/. Soc. Mot. Pict. Eng., XLI (July, 1943), p. 101.

DISCUSSION

MR. OFFENHAUSER: Mr. Thompson's paper contains much food for thought
and raises a number of important related questions. Let us consider his recom-
mendation of the Griswold Jr. splicer with a Vie-inch splice.

For more than two years all splices made in original films in our laboratory
have been made with a hot-splice type Bell & Howell laboratory splicer, con-
verted to make a 0.070-inch straight splice. The splicer is accurately adjusted
to produce a 0.010-inch overlap on either side of the sprocket-hole. On the right
side of the splicer, an extension guide has been added that is quite long relative
to the width of the film. This guide, which is chromium plated, makes it im-
possible to "skew" the film on the right side of the splicer with respect to the
film on the left side of the splicer; the alignment of a splice is almost as good as
that of a continuous piece of film.

The scraper for the splicer is very important ; it is accurately adjusted for depth
of cut and is kept honed by regular day-to-day maintenance. Splices are checked
under a microscope regularly every day to make certain that nothing was damaged
in the previous day's operations.

To those who inspect splices under a microscope (and for commercial 16-mm
film, all of us should do so), the use of a Griswold Jr. splicer seems really crude.
While it is probably one of the best, if not the best, hand-type splicer on the
market, its shortcomings are such that our laboratory discarded it over two years
ago. These shortcomings are:

(1) It does not produce a "hot" splice.

(2) It can not be adjusted to provide equal overlap on either side of the
sprocket-hole.

(3) When adjusted, it does not retain its adjustment.

(4) It is not readily readjusted. (Readjustment is required periodically for
every splicer.)

The characteristics of a splicer alone, however, do not tell the whole story;
the question of the skill with which the splicer is used is so often a controlling
factor that the mere possession of the best splicer is no assurance of the best results.

I am definitely not in favor of the Griswold Jr. splicer. Nothing less than the
modified Bell & Howell laboratory splicer is suitable for large-scale high-quality
work; an operator can make 50 per cent more splices per day with far less effort
and fatigue. Every splice made should be a good one — and, with proper care,
will be.

Very little maintenance attention is needed for the Bell & Howell splicer pro-
vided that those who use it are fairly skillful; however, a careless or unskilled
person can, in a matter of seconds, put the splicer out of commission for a half-
hour or longer. Adequate training of a careful person requires but a few hours
if that person has the necessary aptitude.

Oct., 1943] DIRECT 16-MM PRODUCTION 349

What has just been said about splicers may be applied to any class of machinery.
To use any machine successfully requires ever- vigilant inspection to assure that
the machine (and the operator) continues to fulfill its purpose. This inspection
not only cures difficulties when and as they arise, but also has as its most important
function the anticipating of difficulties before they have grown to significant magnitude.

In a broader sense, this identical line of reasoning has already been successfully
applied to armament production. Before a contractor who is to manufacture
materiel receives the "green light," he must prove his ability to produce the
desired product with the required quality — and to prove also that he can con-
sistently maintain that quality in mass production. It is common practice that
one or more of the successful samples is referred to when checking the product
being currently produced. It has been the unswerving adherence to this policy
that has made possible the manufacture of superior war supplies by manufac-
turers of refrigerators, automobiles, elevators, and a host of other peacetime
products.

It would seem that this principle which has been so successful in armament
procurement should be equally successful in the procurement of prints of our
training films. Our laboratory industry has a tremendous advantage over the
automobile industry and the refrigerator industry in the solution of the problem ;
the product of the film laboratory is not sensibly different in wartime from what
it is in peacetime. The advantage should be reflected in the superiority of the
product manufactured.

War has demanded a steady lifting of the quality level of all armament materiel ;
it should likewise demand a steady lifting of the quality level of all 16-mm prints
of training films manufactured. This improvement can be readily obtained if
our Government contracts will stress the product to be produced; and specify
that product in measurable physical terms. The possession of a good bank
statement and credit references together with particular facilities and special
kinds of machinery such as Cinex testers and the like has no effect whatever upon
the quality of the desired products: prints of training films.

There is dire need for rigid inspection of prints of training films and for quality
specifications that will be sure to reject all defective prints. The all-too-common
philosophy of "it costs too much to reject defective prints" and "it is good enough,
anyhow" aggravates an already serious situation. We can be thankful that this
sort of delusion was not shared by those who supplied the guns and bullets to
the men on Guadalcanal.

Ever- vigilant inspection can do as much to improve the quality of 16-mm
prints as it does to improve the quality of our ordnance. Let's give it a chance
by specifying the product, and not the tools that someone happens to use to make the
product. Let us have rigid inspection under product specifications, and enjoy
the benefits of improved quality and lower costs resulting therefrom.

MR. TUTTLE: There has been and still is considerable confusion on the part
of many users of Kodachrome film on the subject of the type of film to use with
different light sources available.

The daylight type of Kodachrome film is suitably color-balanced so that it
matches the color temperature of sunlight and blue sky which normally prevails
in outdoor photographic work. The average mixture of sunlight and blue sky
has a color temperature of about 6100° Kelvin. Therefore, the daylight type of

350 L. THOMPSON

Kodachrome film is suitably color-balanced to match it. The Type A or arti-
ficial-light Kodachrome film is suitably color-balanced to match the photoflood
type of illumination which has a color temperature of approximately 3450°
Kelvin when used on a 120-volt line.

Filters were made available for these two films principally to permit the use of
short unexposed pieces of film, remaining in the camera, in different types of
illumination than originally specified. Rather than discard the film when the
illumination is changed, it may be exposed by using the proper filter. For this
purpose the No. 80 filter, which is light blue in color, was made available for use
on the camera lens when daylight-type Kodachrome film is to be used indoors
with photoflood illumination. The No. 85 or orange-colored filter was made
available for use with the Type A film in using the short lengths of film out-of-
doors. It is not the intention of the manufacturers of Kodachrome film that
either film should be used as an all-purpose film with filters hi opposite types of
lighting for which the film was manufactured.

For the most satisfactory results on Kodachrome film the daylight type of
film should be used when pictures are made in the normal mixture of sunlight
and blue sky; Type A Kodachrome film should be used with the photoflood type
of lamp on a line of proper voltage.

There are many factors relating to the use of filters with various light-sources
which enter into such a discussion, and the technical reasons for not using filters,
unless necessary, are many and require a much lengthier technical discussion
than is permissible here. However, it is sufficient to say that if daylight type
of Kodachrome film is used in sunlight and the Type A Kodachrome film is used
with either the No. 1 or No. 2 photoflood lamps; and if a color-temperature meter
is used to check the color quality of the light-source to make certain that it is
approximately 3450 ° Kelvin, the best possible color rendition will be obtained on
each type of film.

RESISTANCE OF GLASS TO THERMAL SHOCK5
CHARLES D. OUGHTON**

Summary. — The resistance of glass to thermal shock may be increased considerably
by tempering which is the controlled introduction of strain. Tempering and annealing
represent opposite extremes in heat treatment. Annealing removes strain by slow
cooling while tempering introduces strain by rapid cooling. Glass fractures originate
in regions of tension. When hot glass is subjected to a cold medium, a thermal
gradient is introduced and the resulting strain distribution places the surface in a
state of tension. If the tension exceeds the tensile strength of the glass a fracture will
occur. Condenser lenses of projection machines are often subjected to thermal shock
of this type. Tempering the glass places the surfaces under compression. A much
greater thermal shock may then be applied without causing fracture, because sufficient
stress must be introduced to completely neutralize the compression before the surface
can go into tension and fail.

The breakage of reflectors, condensers, and occasionally projection
lenses from heat is a common occurrence in lanterns with high in-
tensity arcs. This is in accord with a number of everyday ex-
periences, such as hot glass cracking when placed in cold water or
touched to a cold object. Such breakage is a result of the tremendous
shock to which glass may be subjected by even a small change in
temperature. When costly optical glass is involved the phenomenon
requires investigation from the practical viewpoint of how to make
glass resistant to thermal shock.

Several general observations concerning glass should be noted.
Glass expands when heated. The fractional amount by which it
expands per degree of temperature rise is known as its coefficient
of expansion. The coefficient varies with the composition of the
glass; for example, glass having a relatively low percentage of silica
has a high coefficient of expansion, while glass with a high silica
content has a low coefficient of expansion. If one section of a plate
of glass is raised to a relatively higher temperature than that of the
surrounding or adjacent glass, the heated portion expands. The

* Presented at the 1943 Spring Meeting at New York.
** Scientific Bureau, Bausch & Lomb Optical Co., Rochester, N. Y.

351

352 C. D. OUGHTON [j. s. M. P. E.

thermal gradient from the heated section to the surrounding glass
with a corresponding change in dimensions introduces stress. When
stress exceeds the tensile strength of the glass a fracture occurs.
Glass having a low coefficient of expansion will permit a greater tem-
perature gradient for a given amount of stress than will glass with a
high coefficient of expansion.

Stress caused by the thermal gradient produces strain in the glass.
Two conditions of strain exist that are of interest in this instance
— tension and compression. Bending a bar of glass places tensional
strain on the side being stretched and compressional strain on the side
being squeezed. A neutral layer of no strain will pass through the
central region of the bar. Glass fractures originate in a region of
tension. Considerable tension may be easily introduced where a
flaw or weakness is present in the glass. Flaws are often micro-
scopic and unnoticeable. It is reasonable to assume that surface
flaws should weaken glass more than internal flaws and, correspond-
ingly, more fractures originate at the surface.

With these considerations in mind, two solutions are available
for increasing the resistance of glass to thermal shock : first, the glass
may be given a high silica content with a correspondingly low co-
efficient of expansion; and, secondly, the glass may be tempered to
place the outer region or surface layers under compressional strain,
thus preventing tension from reaching the surface flaws. This latter
approach presents rather interesting results.

Tempering involves a heat treatment that is the opposite extreme
to annealing. Annealing consists of slow cooling to remove strain.
Tempering introduces strain by rapid cooling. In both instances
the glass is heated to a temperature slightly below the softening
temperature. In this temperature range the stress is completely
removed from the glass. By cooling slowly to room temperature,
over a period of hours, the glass assumes an unstrained or annealed
condition. By cooling the glass to room temperature in an interval
of a few minutes, in a stream of air or by immersion in a liquid bath,
the glass is placed in a strained condition and is said to be tempered.

If tempered properly such glass is capable of resisting considerably
more thermal and physical shock than annealed glass. It is placed
on the market under a variety of trade names and is used in laboratory
glassware, safety goggles, car windows, etc., where physical and
thermal shocks are likely to occur.

An examination of the strain conditions in tempered glass will

Oct., 1943 j RESISTANCE OF GLASS TO THERMAL SHOCK 353

indicate, in general, how the glass is made resistant to thermal shock.
To explain in detail the origin and conditions of strain in tempered
glass is beyond the scope of this paper. It will be sufficient to state
that in tempered glass the entire surface region is in a state of com-
pressional strain ; the center is under tension, and between the center
and the surface there is a neutral zone of isotropic strain. When hot
glass is suddenly cooled the outer region solidifies over an expanded
hot central region. As the central region is cooled to room tem-
perature by the cold surface, it can not contract to its normal dimen-
sions because of the solidified but expanded outer surface of the glass.
This leaves the center under tension.

Remembering that in untempered glass fractures originate at
surface flaws when the tension around the flaw exceeds the tensile
strength of the glass, it is apparent that the state of strain introduced
into the glass by tempering should increase its resistance to thermal
shock. Before the tensional stress at the surface can exceed the
tensile strength of the glass after tempering, it must counteract the
compressional stress that has been introduced over the complete
surface. Thus, a more severe shock is required to fracture tempered
glass than untempered glass. When tempered glass does fracture
indications show that the break often originates in the central ten-
sional region.

Glass is most likely to break when it is plunged suddenly from a hot
medium into a cold medium. In heating untempered glass from room
temperature to a much higher temperature (cold to hot thermal
shock), the surface is placed in a state of temporary compressional
strain. Thus there is little chance of a break originating under this
condition. But, when glass is cooled rapidly from a high temperature
to a low temperature, the surface is placed in a state of temporary
tensional strain and a fracture is likely to occur. Condenser lenses
of projection machines are almost constantly subjected to thermal
shock of this latter type. Their fracture is a familiar and frequent
occurrence, and therefore the lenses serve as excellent examples for
the application of the above principles.

Properly annealed condenser lenses of the highest illuminating
efficiency, even when made of the best thermal shock-resistant
glass, have a very brief life when used with high-intensity arcs. This
is due to the tremendous thermal shock to which the lenses are sub-
jected. Only a few inches from the piano side of the condenser is a
carbon arc carrying, perhaps, 175 amperes which acts as a source of

354

C. D. OUGHTON

[J. S. M. P. E.

heat. While this side of the lens is held at a high temperature, the
opposite side radiates the heat and has a considerably lower tem-
perature. The result is a thermal gradient that may cause fracture.
Ordinary optical crown glass would last only a few minutes under
these conditions. Even well-annealed Pyrex glass with a much
lower coefficient of expansion fails to withstand such thermal shock
for a reasonable length of time. A solution to the problem is found
in fused silica, often referred to as fused quartz, with Vith the co-
efficient of expansion of Pyrex. Fused silica is expensive to prepare,
but serves satisfactorily until the surface becomes pitted from the
arc.

(a) 0)

FIG. 1. Polariscope strain patterns in condenser lenses (a) before and (&)
after use with source of heat on piano side. The increased number of bands
in (&) indicates that the compressional strain on the piano side has been
partially removed.

A lens made of glass having a low coefficient of expansion, such as
Pyrex, will also last until the surface becomes pitted if it is tempered
properly. However, the life of a tempered lens is limited by the
temperature to which the surface near the arc is heated. When
used with a high-intensity arc the tempered lenses will eventually
break. A comparison of the strain pattern in a condenser lens after
tempering and again after 50 hours' use in a motion picture pro-
jector, using a 175-ampere arc, reveals a rather startling phenomenon:
the lens appears to have more strain after use than before.
Fig. 1 illustrates this difference: (a) is a photograph of the strain

Oct., 1943] RESISTANCE OF GLASS TO THERMAL SHOCK

355

pattern of a tempered condenser lens in plane polarized light before
being subjected to the treatment described above; (b) shows the lens
after use. The additional dark bands indicate the change in the

FIG. 2. (a) Polariscope strain pattern in a glass strip
tempered symmetrically from top and bottom with air.

(&), (c), and (d). The same strip after successively in-
creasing periods of heat application to the lower surface.
The arrows indicate the neutral band of zero resultant stress.
The outside of the glass is under resultant compressional
strain and the inside under resultant tensional strain. The
decrease in the number of neutral bands between the neutral
layer and the lower surface shows that the heat treatment
has progressively relieved the compressional stresses in this
region.

amount of resultant strain. From the analysis of the method of
introducing strain into glass it may be concluded that no strain has
been added, because the glass temperature did not reach the annealing

356 C. D. OUGHTON [j. s. M. p. E.

range and it received a gradual chilling in cooling to normal, whereas
it originally received a severe chilling.

The solution to this problem is found in the manner by which the
lens is heated in the projector. The piano side of the condenser lens
is usually placed only a few inches from the carbon arc source.
Carbon arcs drawing a high current act as a source of con-
siderable heat that raises the temperature of the piano side of the
condenser thus decreasing the viscosity of the glass and permitting
the gradual release of the surface layers of strain. This is shown
in Fig. 2. A strip of glass 4 in. long, 3/4 in. wide and y2 in. thick was
air tempered. Fig. 2 (a) shows the strain pattern in the strip as a
result of cooling uniformly on the upper and lower sides. Con-
siderable heat was then applied to the lower side of strip (a) . Fig. 2
(b), (c), and (d) show the gradual release of strain as the heat was
applied for successively increasing lengths of time. The arrow
marks the neutral line of zero resultant stress. The decrease in the
number of dark bands between the neutral line and the surface gives
a measure of the decrease in the compressional strain on the surface
of the glass. Considerably more strain was released on the side
heated owing to the lower viscosity of the glass in that region. Be-
cause the temperature in a condenser lens varies from a high value
on the piano side to a low value on the convex side, more strain should
be released on the piano side. The center and convex side of the
lens tend to remain in tensional and compressional states of strain
as limited by the viscosity of the glass which will vary according to
the heat distribution. The strain pattern in the lens following ex-
posure to a high temperature for some time gives indications of con-
siderably more strain. Previously, the strain viewed in the polar i-
scope was made up of compression on the convex side, minus tension
in the central region, plus compression on the piano surface which,
in the usual methods of tempering thick lenses, will add up to re-
sultant tension. This tension is indicated in the polariscope by a
series of colored bands. After use the strain pattern is made up of
compression on the convex side, minus tension in the central region,
plus less compression than previously on the piano side. This gives
a greater resultant tension which is indicated in the lens by an in-
crease in the number of colored bands (Fig. 1). Actually, there is
less strain in the lens, and also a less effective distribution of the re-
maining strain.

Over a period of time the compressional strain on the piano side

Oct., 1943] RESISTANCE OF GLASS TO THERMAL SHOCK 357

will be released sufficiently to permit the surface flaws to enter a
state of tension and cause a fracture. To counteract this release
of strain special tempering techniques have been and are being de-
veloped to place a thicker layer of compression on the glass surface.
Although tempered glass will not endure indefinitely under severe
thermal shock, tempering must be considered as a useful method
of increasing the resistance of glass to thermal shock. One of the
best examples of its usefulness is found in condenser lenses. Whereas
annealed condensers under severe thermal shock in motion picture
projectors will last only a few hours, the tempered condensers will
last until the surface becomes pitted.

CURRENT LITERATURE OF INTEREST TO THE MOTION PICTURE

ENGINEER

The editors present for convenient reference a list of articles dealing -with subjzcts
cognate to motion picture engineering published in a number of selected journals.
Photostatic or microfilm copies of articles in magazines that are available may be
obtained from the Library of Congress, Washington, D. C., or from the New York
Public Library, New York, N. Y., at prevailing rates.

American Cinematographer

24 (Mar., 1943), No. 3

Shooting Action Movies in the African Desert (p. 86)
"Special-Effects" and Wartime Production (p. 89)
Direct 16-Mm vs. 35-Mm for Training Film Production

(p. 91)

A "Model EE" Grows Up (p. 96)
Professionalizing the Bolex (p. 98)
Practical Pointers on 16-Mm Sound Projection (p. 102)

24 (May, 1943), No. 5
Filming Desert Victory (p. 167)

Hollywood Greets Four Soviet War Camera-Aces (p. 168)
Exposure Control in Aerial Photography (p. 170)

24 (June, 1943), No. 6
"Cheating" on Camera- Angles (p. 217)
Care and Operation of 16-Mm Sound Projectors (p. 218)
More about "Strobo-Sync" (p. 222)

24 (July, 1943), No. 7
Screen Tests Aren't Necessary! (p. 249)
The Rhapsodic Technique (p. 250)
Hollywood's Own War Plants (p. 252)

O. H. BORRADAILE

B. HASKIN
W. A. PALMER

P. A. JACOBSON
W. STULL
J. W. BOYLE

D. MACDONALD

W. STULL

D. W. NORWOOD

R. MATE

D. L. CONWAY
S. JEPSON

C. R. ROGERS

E. S. ROBERTS
W. STULL

British Kinematograph Society, Journal

6 (Apr., 1943), No. 2
Acoustics in the Motion Picture Theater and Studio N. FLEMING

(p. 48)
A 35-Mm Film Pitch Measuring Instrument (p. 63) L. J. WHEELER

Communications

23 (May, 1943), No. 5
High-Fidelity Systems, Pt. II (p. 24)
358

A. J. EBEL

CURRENT LITERATURE

359

Educational Screen

22 (May, 1943), No. 5
Motion Pictures— Not for Theatres, Pt. 47 (p. 170)

22 (June, 1943), No. 6
Motion Pictures — Not for Theatres, Pt. 48 (p. 206)

Electronics

16 (Mar., 1943), No. 3
Pictures by Wire and Radio (p. 112)

Sound Recording Depends upon Electronics (p. 114)

Institute of Radio Engineers, Proceedings

31 (Mar., 1943), No. 3

The Focusing View-Finder Problem in Television Cam-
eras (p. 100)
Mercury Lighting for Television Studios (p. 106)

International Projectionist

18 (Feb., 1943), No. 2

Analysis of a Bridging Amplifier, Pt. IV (p. 7)
Sound and Projection Equipment in War Department

Theatres, Pt. I (p. 9)
Review of Projection Fundamentals, Pt. VI (p. 16)

18 (Mar., 1943), No. 3

Sound and Projection Equipment in War Department
Theatres, Pt. II (p. 16)

18 (Apr., 1943), No. 4

Practical Pointers on 16-Mm Sound Projection (p. 7)
Two Resistance-Coupled Voltage Amplifiers (p. 9)
Peacetime Planning Means Wartime Projection Room
Efficiency (p. 18)

18 (May, 1943), No. 5

A Modern Inverse Feedback Amplifier (p. 7)
I. P. Contestants Tackle Crackling and Popping Noises
in Sound Systems (p. 10)

18 (June, 1943), No. 6

16- vs. 35-Mm Projection in Army Training Camps (p. 7)
Technical Analysis of a Sound System for Small Theatres
(P- 9)

18 (July, 1943), No. 7
Quality Essential in P. A. Systems (p. 7)
Unusual Effects Produced with Discarded Equipment

(p. 12)

A Complete Study on the Prevention of Film Damage
(p. 16)

Motion Picture Herald

151 (Apr. 24, 1943), No. 4
16-Mm Field Expanding to Big Business Status (p. 15)

A. E. KROWS
A. E. KROWS

A. G. COOLEY AND

L. DECKER
C. R. KEITH

G. L. BEERS
H. A. BREEDING

L. CHADS OURNE
G. L. BUB

G. L. BUB

J. W. BOYLE
L. CHADBOURNE
W. BENNETT

L. CHADBOURNE

A. NADELL

L. CHADBOURNE

L. CHADBOURNE
F. BENDELL

H. B. SELLWOOD

FIFTY-FOURTH SEMI-ANNUAL TECHNICAL CONFERENCE

OF THE

SOCIETY OF MOTION PICTURE ENGINEERS

HOLLYWOOD-ROOSEVELT HOTEL, HOLLYWOOD CALIF.
OCTOBER 18th-22nd, INCLUSIVE

Officers and Committees in Charge

HERBERT GRIFFIN, President

EMERY HUSE, Past-President and Chairman, Local Arrangements

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W. C. KUNZMANN, Convention Vice-P resident

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. C. R. DAILY, Chairman

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Reception and Local Arrangements

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H. J. CHANON M. S. LESHING G. F. RACKETT

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C. W. HANDLEY P. MOLE C. R. SAWYER

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J. K. HILLIARD H. W. MOYSE J. R. WILKINSON

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Registration and Information

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360

FIFTY-FOURTH SEMI-ANNUAL CONFERENCE 361

Publicity Committee

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J. W. BOYLE JULIUS HABER

C. R. DAILY C. R. KEITH

G. GIBSON E. C. RICHARDSON

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LOREN L. RYDER, Chairman

A. M. GUNDELFINGER P. MOLE R. R. SCOVILLE

H. T. KALMUS H. W. MOYSE S. P. SOLOW

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Hotel and Transportation

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H. J. CHANON G. T. LORANCE N. L. SIMMONS

L. E. CLARKE W. C. MARCUS W. L. THAYER

Projection Committee

35-Mm Programs
R. H. McCuLLOUGH, Chairman
L. R. ABBOTT W. E. GEBHARDT, JR. C. R. SAWYER

B. FREERICKS W. W. LINDSAY, JR. W. V. WOLFE

C. R. RUSSELL
Officers and Members of I.A.T.S.E. Locals 150 and 165

16-Mm Programs

H. W. REMERSHIED, Chairman

A H. BOLT A. M. GUNDELFINGER

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MEMBERS OF THE SOCIETY

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FRANKLIN C. GILBERT

ISRAEL H. TILLES

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

VOLUME XLI • • • NOVEMBER, 1943

CONTENTS

PAGE
A Motion Picture Arc-Lighting Generator Filter

B. F. MILLER 367
Notes on the Application of Fine-Grain Film to 16-Mm

Motion Pictures W. H. OFFENHAUSER, JR. 374

Planning for 16-Mm Production R. C. HOLSLAG 389

Precision Recording Instrument for Measuring Film

Width S. C. CORONITI AND H. S. BALDWIN 395

Conservation of Photographic Chemicals A. HAINES 409
Maps on Microfilm — Some Factors Affecting Resolu-
tion M. BRUNO 412
Sensible Use of Refrigerants under the Emergency
Now Confronting the Industry

A. C. BUENSOD AND R. W. WATERFILL 426

Film Conservation Methods — -A Symposium : 432

Film Conservation Methods at Universal Studios

G. J. DEMoss 434
Film Conservation Methods at Republic Studios

D. J. BLOOMBERG AND J. STRANSKY 437
Film Conservation Methods at RKO Studios

P. E. BRIGANDI 442
Film Conservation Methods at Columbia Studios

S. J. TWINING 444
Film Conservation Methods at Paramount Studios

I. M. CHAMBERS 449
Film Conservation Methods at Samuel Goldwyn

Studios D. A. NEWELL 455

Film Conservation Methods at Walt Disney Pro-
ductions C. O. SLYFIELD 457
Film Conservation Methods at Warner Bros. Studios

G. M. BEST 459
(The Society is not responsible for statements of authors.)

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

HARRY SMITH, JR., EDITOR

ARTHUR C. DOWNES, Chairman

Board of Editors

JOHN I. CRABTREE ALFRED N. GOLDSMITH EDWARD W. KELLOGG
CLYDE R. KEITH ALAN M. GUNDELFINGER CHARLES W. HANDLEY

ARTHUR C. HARDY
Officers of the Society
**President: HERBERT GRIFFIN,

90 Gold Street, New York, N. Y.
**Past-President: EMERY HUSE,

6706 Santa Monica Blvd., Hollywood, Calif.
** Executive Vice-President: LOREN L. RYDER,
5451 Marathon Street, Hollywood, Calif.
^Engineering Vice-President: DONALD E. HYNDMAN,

350 Madison Avenue, New York, N. Y.
**Editorial Vice-President: ARTHUR C. DOWNES,

Box 6087, Cleveland, Ohio.
* Financial Vice-President: ARTHUR S. DICKINSON,

28 W. 44th Street, New York, N. Y.
** Convention Vice-President: WILLIAM C. KUNZMANN,

Box 6087, Cleveland, Ohio.
^Secretary: E. ALLAN WILLIFORD,

30 E. 42nd Street, New York, N. Y.
^Treasurer: M. R. BOYER,

350 Fifth Ave., New York, N. Y.
Governors

*H. D. BRADBURY, 411 Fifth Avenue, New York, N. Y.
*FRANK E. CARLSON, Nela Park, Cleveland, Ohio.
* ALFRED N. GOLDSMITH, 580 Fifth Avenue, New York, N. Y.
*A. M. GUNDELFINGER, 2800 S. Olive St., Burbank, Calif.
*CHARLES W. HANDLEY, 1960 W. 84th Street, Los Angeles, Calif.
•EDWARD M. HONAN, 6601 Romaine Street, Hollywood, Calif.
*JOHN A. MAURER. 117 E. 24th Street, New York, N. Y.
**WILLIAM A. MUELLER, Burbank, Calif.

"Term expires December 31, 1943.
**Term expires December 31, 1944.

Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.

Publication Office, 20th & Northampton Sts., Easton, Pa.

General and Editorial Office, Hotel Pennsylvania, New York, N. Y.

Entered as second-class matter January 15, 1930, at the Post Office at Easton,

Pa., under the Act of March 3, 1879. Copyrighted, 1943, by the Society of Motion

Picture Engineers, Inc.

A MOTION PICTURE ARC-LIGHTING GENERATOR FILTER

B. F. MILLER^

Summary. — The general means heretofore employed to reduce the commutator
noises emitted by arc lamps operated from direct current generator sets is outlined, and
the deficiencies of such equipment are noted. The design of an electrical filter unit,
which is extremely compact as compared to previously employed equipment and which
is capable of handling the full load output of studio stage-lighting generators, is
described. This filter completely suppresses all arc-lamp noises resulting from
generator commutator ripple, may be permanently associated with any studio genera-
tor set, eliminates the need for repeated installations of large numbers of choke coils
on the set, and requires no servicing. The unit is capable of withstanding current
overloads in excess of 100 per cent indefinitely.

The "whistle" present in arc lamps owing to the commutator ripple
of the power supply generators has caused recording engineers endless
difficulty since the advent of sound motion pictures. Many attempts
have been made to minimize or to eliminate this noise, but so far
as is known, none of the remedies heretofore proposed has been en-
tirely successful. Almost all the studio generator equipment is
shunted by large electrolytic condensers, and in a few instances
several turns of heavy copper cable have been employed as an air-
core inductance in series with the load circuit. Such air-core induc-
tances are not entirely satisfactory, however, since the attainment of
sufficiently high values of inductance is usually accompanied by the
introduction of excessive amounts of resistance in the load circuit.

In addition to the overall filtering described above, it has been
customary to employ large air-core chokes, each having a current-
carrying capacity of approximately 1000 amperes, on each set utilizing
arc lamps. Some five feet in diameter and weighing approximately
a half-ton, each of these chokes is capable of providing a certain
amount of filtering to a load consisting of eight to twelve arc lamps.
These chokes are commonly mounted on dollies so that they may be
transported from set to set.

* Warner Bros. Pictures, Inc., Burbank, Calif.

367

368 B. F. MILLER [j. s. M. P. E.

Since the combined filtering provided by the individual chokes on
the set and that of the generator filters is usually insufficient to pre-
vent audible noise from the arc lamps, additional filtering is generally
provided for each lamp in the form of small iron-core choke coils or
"whistle-boxes," each weighing approximately 50 Ibs.

Under extremely favorable circumstances this filtering combina-
tion is sufficient to eliminate the bulk of the objectionable singing
noise characteristic of arc-lamp operation. Under more adverse con-
ditions, however, recordings are still marred by arc-lamp background
noise. A further reduction in lamp noise may be made through
first-class maintenance of generator equipment, since commutator
ripple magnitude is partially determined by the condition of gen-
erator commutators and brushes. However, a definite lower limit of
ripple voltage exists for each generator unit; when this limit has
been attained the remaining necessary reduction in ripple voltage
must be achieved through the use of electrical filtering devices.
Technicolor productions are particularly susceptible to lamp-noise
trouble, since arc-lighting is used almost exclusively for color photog-
raphy.

In addition to the fact that complete suppression of lamp noise is
extremely difficult with the type of filtering described, the transporta-
tion and rigging of the large number of choke coils necessary for
each operating set is time-consuming and costly. A more desirable
form of filtering would therefore provide the following features :

(1) Complete suppression of all commutator ripple noise from arc
lamps, with an adequate margin of safety for highly variable lamp
loads and for variations in magnitude of generator-ripple voltage.

(2) A single filter unit which could be permanently associated with
a lighting-generator set.

(3) A unit whose general design would prove adequate for a
variety of generator types.

(4) A unit which would provide adequate filtering even though the
generator unit with which it was associated might frequently be sub-
jected to moderate overloading.

(5) An essentially compact unit, so that it might be conveniently
installed adjacent to its associated generator.

The desirability of designing a unit possessing these features was
recently called to the attention of the writer by Mr. Lee Adams of
Warner Bros. Electrical Department. The remainder of this paper
is devoted to an outline of the unit designed and a brief summary of

Nov., 1943] ARC-LIGHTING GENERATOR FILTER

the conclusions reached since the units have been employed in pro-
duction.

A number of noise-level studies were first made on typical arc lamps
with the aid of a General Radio sound-level meter. During the studies
it was determined that arc-lamp noise would be reduced to a negli-
gible value if the generator ripple was reduced by a factor of approxi-
mately 30 decibels. Oscillographic studies were next conducted to
determine the magnitude and frequency distribution of the principal
ripple-voltage components present in the generator terminal voltage.
The data so obtained indicated a predominant low-frequency com-
ponent of approximately 900 cycles per second, having an amplitude
of about three volts, as well as numerous higher frequency compo-
nents of equal or lesser magnitudes. Tests on several similar generators
indicated that the data obtained from the first unit tested might be
taken as typical.

The full-load current rating of the generators involved was 1200
amperes, and the terminal voltage of the machines was 120 volts.
The minimum normal load impedance, neglecting any inductance
present in stage feeder circuits, was therefore equal to 0.10 ohm.
After some consideration it was decided to design a simple "constant
k"* prototype section generator filter which would have a character-
istic impedance of 0.05 ohm and would provide a minimum of 40
decibels attenuation to the lowest frequency ripple component pres-
ent in the generator terminal voltage. This choice was based upon
the following grounds :

(1) Since the filter would be terminated in a highly variable load
impedance, the variation in filtering attained would be minimized if
the filter characteristic impedance were made lower than the lowest
value of generator load impedance.

(2) Because of the large number of high-frequency commutator
ripple components present at the generator terminals, it was necessary
to insure that adequate filtering would be provided over a very wide
frequency band ; this could most readily be accomplished through the
use of prototype filter sections.

* Ed. Note: A "constant k" type filter is one for which the relation ZiZ2 =
k2 holds, where Z\ = the impedance of the series arm and Z2 = the impedance of
the shunt arm. An "Af-derived" type filter is one in which the image impedances
are equal to those of a "constant k" type but whose configuration, attenuation,
and phase characteristics are, in general, different from those of the constant k
type. (See "Transmission Networks and Wave Filters," T. E. Shea, D. Van
Nostrand Co., 1929, Chap. VII.)

370

B. F. MILLER

[J. S. M. P. E.

(5) The incorporation of Jkf-derived filter sections would have
necessitated the use of a larger number of filter elements and would
make the effectiveness of the filter somewhat variable with different
types of generator equipment.

A preliminary study of the filter requirements led to the conclusion
that the most economical design would consist of one and one-half
prototype low-pass sections, having a cut-off frequency of approxi-
mately 400 cycles per second. Upon setting the filter characteristic
impedance equal to Z0 and the filter cut-off frequency equal to fc, the

0.0 £0

0.040 MH.

smtt<

— — o

PUT

mm mm

5 OUT PUT

I5,ooo r*fd.

7,600 Mfd.

FIG. 1.

0.040 r"»H. O.O40 r»7H.

0000000

+— — o

PUT -

•i tm

2 OUT PUT

15,000 rtftt.

15,000 M^d

> ft

FIG. 2.

required inductance L and capacitance C for the prototype section
were determined from the well known relationships :

Upon setting Z0 = 0.05 and fe = 400, the required value of L be-
comes equal to 40 microhenries and that of C equal to 15,900 micro-
farads. The latter value was actually reduced to 15,000 micro-
farads, since it could then be constructed readily by employing six
2500-microf arad capacitor banks.

Employing the L and C values just derived the filter took the form
shown in Fig. 1. Calculations of the core size required for the filter

Nov., 1943] ARC-LIGHTING GENERATOR FILTER 371

inductances were next carried out with the aid of formulas previously
derived from extended studies on transformer and reactor designs.
From these it was determined that a core consisting of approximately
113.5 Ibs of transformer A grade silicon steel would suffice if a normal
maximum core flux density of 10 kilogausses was employed. Allowing
a normal maximum of 400 amperes per square inch of winding cross-
sectional area, the coil copper requirements were calculated as 53.5
Ibs.

FIG. 3. The new- type filtering equipment used
on a set requiring 5000 amperes.

The volume of iron and copper required for the 40-microhenry in-
ductance was considered sufficiently small to make it desirable to
employ identical inductances in both filter sections. An additional
margin in the amount of filtering provided could also be obtained at
moderately low cost by employing identical capacitor banks at both
points in the filter. Accordingly, the initial design was modified to
that shown in Fig. 2. This unit is capable of producing an average
of approximately 50 decibels attenuation to ripple frequencies of
about 900 cycles per second or, roughly, 20 decibels more than the
amount actually required. Higher ripple frequencies are attenuated

372

B. F. MILLER

[J. S. M. P. E.

in a somewhat greater degree. Sufficient copper and iron are pro-
vided in the filter inductances so that overloads of fifty per cent may
be tolerated with only a minor reduction in the degree of filtering
attained.

The filter inductances as finally constructed consist of a single-
turn solid-cast copper winding having a length of 57 inches, a cross-
section of 3 square inches, a weight of 55 Ibs, and a resistance of
0.00002 ohm. The core consists of a 20-inch stack of high-silicon steel
laminations weighing 120 Ibs and is provided with a Vie-mch ajr gap
to satisfy inductance requirements. When the coil is carrying 1200

FIG. 4.

The old-type filtering equipment used on a set requiring
5000 amperes.

amperes d-c, the inductance is 40 microhenries, and is considerably
higher than this value at lower values of load currents. The full-load
voltage drop across the inductance is approximately 25 millivolts
which is negligible. Normal full-load power dissipation in the coil
winding is but 30 watts.

The experimental filter constructed in accordance with the above
design proved so satisfactory on tests that a sufficient number of
additional units have been constructed to equip every fixed and
portable generator in the studio. Since these installations were com-
pleted not a single case of trouble from arc-lamp whistle has been re-
ported, and the filter has proved satisfactory even when carrying an
overload of 1500 amperes. Figs. 3 and 4 compare the new and old
filtering equipment on a set requiring 5000 amperes.

Nov., 1943] ARC-LIGHTING GENERATOR FILTER 373

The advantages and economies resulting from these installations
may be summarized as follows :

(1) The filters eliminate all commutator ripple noise from arc
lamps.

(2) All combination and individual arc-lamp chokes are eliminated,
resulting in a saving of time on the sets, a saving in labor formerly
required for transporting and installing the chokes, and in main-
tenance costs on individual chokes.

(3) The filters are effective at all values of load current, introduce
no appreciable voltage drop in the load circuit, and require no main-
tenance of any kind.

(4) There is a great saving in cost and in the use of critical mate-
rials owing, in no small measure, to the fact that the new filter in-
ductances require only one-fourteenth as much copper as formerly re-
quired for a single large-size stage choke coil.

ERRATUM

In the October, 1943, issue of the JOURNAL, Equation (5) on p. 286 of the
paper by Ellsworth D. Cook entitled "The General Electric Television Film
Projector," should read as follows:

NOTES ON THE APPLICATION OF FINE-GRAIN FILM TO
16-MM MOTION PICTURES*

WM. H. OFFENHAUSER, JR.**

Summary.— In September, 1939, J. A. Maurer reported in the JOURNAL on "The
Present Technical Status of 16- Mm Sound-Film" and in November, 1940, on "Com-
mercial Motion Picture Production with 16-Mm Equipment." The first paper com-
pared the quality of direct 16-mm sound with that of reduction prints from 35-mm
negatives; the second compared the graininess of prints by the reversal (intermediate
fine-grain duplicate negative) fine-grain print method with reduction prints from 35-
mm original negatives. The comparison appeared so favorable to direct 16-mm that
the next step was obvious: to put the procedures into commercial use.

Early experience with Dupont fine- grain materials in 1930 and 1931 left behind
an elementary yet important consideration: if the expected improvements from the
use of fine-grain materials and methods were to materialize, something more than the
mere use of fine-grain materials was required. Muck in developer, fixer, and wash
water must be reduced; films must be properly dried. Only with these elementary
conditions satisfied could the quality be significantly improved.

Dupont was the first manufacturer to offer fine-grain release print film to the 16-mm
market; the experience with Dupont 605 was so satisfactory commercially that all
ordinary positive materials were dropped entirely. Eastman 5203 was found to be
the best duplicate negative material available; all other materials were dropped. For
original negatives in 16-mm direct sound recording, Agfa 250, a high-resolving-power
yellow-dye film, was the first satisfactory material on the market and remained without
competitors for several years. With such excellent materials under accurate control,
decidedly improved films were bound to result.

It is interesting to note that these present-day materials have a resolving power of
the order of 100 lines per mm; this is of the same general order as that of the materials
that Dupont produced experimentally in 1931. While resolving power of this order
is considered sufficient for better-grade present-day projectors, there is real need for
pushing the quality standard still farther upward to 150 lines per mm. The tech-
niques for the manufacture of such materials are fairly well known today; the big need
is for Government contracts to call for such high-grade materials and for Government
inspectors rigidly to reject inferior materials such as ordinary positive prints.

The selection of the most suitable materials and the manner of determining the
operating conditions for the machinery selected are described.

Introduction. — When a new 16-mm print is removed from its ship-
ping container for the first time and placed on a projector for its first
run before a professional audience, there is a momentary silence; the

* Presented at the 1943 Spring Meeting at New Yor k.
** Precision Film Laboratories, New York.

374

APPLICATION OF FINE-GRAIN FILM 375

audience evaluates quickly the quality of the projected picture and
sound. As matters stand today, a user has no way of knowing before-
hand just what the quality of his print is going to be; there is no
quality standard for 16-mm prints.

It is no longer true that the output of 16-mm prints is so small and
the distribution so restricted that a quality standard of some sort
would not be welcome. With millions of feet of film pouring out of
laboratories each week at Government expense and with user groups
varying in size from three or four to as many as 1000, some sort of
quality measure would seem sorely needed.

Standardization of 16-Mm Equipment. — For some time we have had
available recommendations concerning the 16-mm sound projector;
these were prepared by the Non-Theatrical Equipment Committee of
the Society at the request of the Committee on Scientific Aids to
Learning, of the National Research Council. Armed with a few facts
about the room in which films are to be projected, it is not a difficult
matter to select the proper size and type of screen and to determine
the lumens output required of the projector. These data are found in
the Report of the Non-Theatrical Equipment Committee published
in the July, 1941, issue of the JOURNAL.

All reputable manufacturers can provide certified data concerning
each type of machine manufactured; all machines of a particular type
are guaranteed to perform as well as the sample machine whose per-
formance has been certified. With the ready availability of such in-
formation and performance guarantees, there is little reason today
why a new machine (when so guaranteed) should not be well suited
to its intended use.

Quality Status of 16-Mm Prints. — If the quality status of 16-mm
prints for such machines is investigated, there appears to be no dis-
tinction between a print suitable for an audience of three or four and a
print suitable for 1000 — unless we accept the term "fine-grain." The
distinction is quite vague; we use the term "fine-grain" for the higher-
grade film, but there is no name at all — or only the name "ordinary
print" — for the other. There is no precise explanation of what "fine-
grain" means or how "fine" a fine-grain film must be to be suitable for
an audience of 1000.

Quality Status of 35-Mm. — As a starting point, consider the quality
of the projected picture and sound in an up-to-date and well-main-
tained 35-mm entertainment theater of 1000 seats. Such a quality
reference is reasonable; it is a convenient reference in which the pic-

376 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

ture is of good quality and the sound is of good quality. The standard
is commercially feasible yet sufficiently high to make the projected
result clearly understandable to the audience; there are no distrac-
tions of poor quality or of extraneous noise to interfere with the sub-
ject matter presented. The projection equipment of the reference
theater has been standardized both for picture projection and for
sound projection. Equipment is as carefully designed to project
sound into all parts of the audience area as to project the picture
properly into that area.

Sixteen-mm non -theatrical equipment has not yet been stand-
ardized to such a high degree; the trend seems to indicate that in this
respect 16-mm will follow in the footsteps of its larger counterpart
and benefit by its progress.

Resolving Power Requirements. — The raw film used for release prints
in the reference 35-mm theater is ordinary nitrate positive; such film
has a resolving power of approximately 55 lines per mm. (Eastman
1301 and Dupont 200 are typical ordinary positive materials.) To
obtain equivalent screen definition from a 16-mm material would re-
quire greater resolution of that material in the ratio of the image
areas; or, more conveniently, in the inverse ratio of the film speeds;
90/36 or 2J/2. Fifty-five lines per mm multiplied by 2x/2 equals 137V2
lines per mm; this is the minimum resolving power required. It is
apparent that ordinary positive 16-mm materials such as Eastman
5301, Dupont 600, and Agfa 220 are woefully inadequate; materials
of far higher resolving power are required for prints that are compa-
rable to 35-mm in quality.

The Resolving Power of Available Materials. — Eastman Kodak has
recently published a welcome book, "Properties and Performance of
Eastman 35-Mm and 16-Mm Films for Professional Use." This
book makes it convenient to choose among the various Eastman ma-
terials available. If we rigidly adhere to our criterion of 137V2 lines
per mm and expect to obtain this result under the "average" develop-
ing conditions therein described, there is but one Eastman material
available, EK 5365, which has sufficient resolving power; the value
is 150 lines per mm. Under the processing conditions specified, this
film is to be developed for 9x/2 minutes in an SD-21 developer with a
lib gamma of 1.40.* Table I shows the available materials, their
suitability, and resolving power.

* SD-21 is the equivalent of a seasoned or partially exhausted D-76 metol-
hydroquinone negative developer.

Nov., 1943]

APPLICATION OF FINE-GRAIN FILM

377

TABLE I
Available Materials, Their Suitability, and Resolving Power

Material

Rated
Resolving
Power
(lines/mm)

Eastman

Dupont

Agfa

Ordinary Positive

55
/ Not \
Recom- J
\ mended /

No. 5301
/ Not \
1 Recom- 1
\ mended /

No. 600
1 Not \
1 Recom- J
\ mended /

No. 220
/ Not \
1 Recom- J
\ mended /

Fine-grain
Positive

No. 5302
/ Satis- \
1 factory I
\ Alternate /

No. 605
(Preferred)

Fine-grain
Dupe Negative

110

No. 5203
(Preferred)

Fine-grain
Master Positive
(Yellow-dyed)

150

No. 5365*
(Preferred)

Sound-recording
Negative

No. 5557
/ Not \
1 Recom- J
\ mended /
No. 5372
(Satis- \
factory J
Alternate /

No. 602
/ Not \
1 Recom- 1
\ mended /

No. 250

(Preferred)

Original Picture

Kodachrome
(Preferred)

Cost Factors— For commercial laboratory use at the present time,
the selection of a material for release printing that would require a
91/ 2- minute developing time is impracticable; with existing equip-
ment, the average laboratory can not afford a developing time
greater than approximately 4 minutes. If we add the additional
cost of the raw film (the price of 5365 is higher than that of ordinary
positive) to the additional processing cost (assuming the develop-
ing time of ordinary positive to be 2 to 3 minutes) the resulting price
would represent such a large percentage increase that some very
extensive and highly expensive persuasion would be required to con-
vince a customer (such as the Government) of the increase in
utility that would justify such an increase in price.

Choice of Positive Materials. — With these very fundamental limi-
tations, it is apparent that the choice of a suitable release print ma-

* Recommended for release prints because of fineness of grain (when developed
in a negative bath that is low in bromide).

378 W. H. OFFENHAUSER, JR. tf. s. M. P. E.

terial is narrowed down to a fine-grain positive type of material that
can be developed with fine-grain and high-resolving-power charac-
teristics in a relatively high-energy developer at a short developing
time. Automatically the choice rests between two materials, East-
man 5302 and Dupont 605. In either case, since a short developing
time is required, a developer high in metol, elon, or rhodol (different
trade names for the same developing agent) is required. The prac-
tical choice between the two film materials will be dealt with later in
this paper.

Economics of Duplicate Negatives. — When the subject of duplicate
negatives and master positives is considered, the economics of the
problem changes. In a sense, duplicate negatives and master posi-
tives are to a film laboratory what special production tools such as
automatic lathes, milling machines, drop forge presses, special jigs
and dies, etc., are to a factory. The automobile industry long ago
pointed out the business wisdom of buying very expensive tools for
mass production; where mass production of prints is the objective,
it would seem to be business wisdom to make the best duplicate nega-
tives and master positives that we know how. If we have a genuine
interest in quality, the problem is to determine what is the best dupli-
cate negative or master positive with little regard for cost — and to go
ahead and make it.

The General Method. — If the original is a direct 16-mm reversal or
Kodachrome, the best black-and-white release prints (all things con-
sidered) that can be made in quantity are made by the duplicate
negative-release positive print method. The emulsion position of the
release print is standard; almost all sound projectors manufactured
are adjusted to proper focus of sound optics for this emulsion position.
Sound is of best quality by this method; we can take advantage of
the distortion cancellation technique that is practically universal for
variable-area film. And last but not least, the contrast of the picture
can be nicely controlled to produce whatever contrast is desired in the
finished print. With such a complement of advantages, the method
may be considered almost ideal.

Some History of Fine-Grain Film. — Before going into the procedure
and how it is worked out, it seems appropriate to record here some of
the unpublished history of fine-grain film that has a direct bearing
upon the materials and methods now employed. In 1930 when John
A. Maurer was working on a sound-on-film arrangement called "The
Talking Book," the resolving power of available sound-recording

Nov., 1943] APPLICATION OF FINE-GRAIN FILM 379

films and of release print materials was poor as measured by present-
day standards. In a variable-area negative, it was quite a feat to
record 5000 cps on 35-mm film with a track density (unmodulated)
of 1.5 and a fog density as low as 0.08; many of us would have felt
overjoyed if we could keep the fog density consistently below 0.06
for a track of 1.6 unmodulated density. We had no special films;
release positive was used for sound negatives as well as for release
prints. Fog due to development was great and the optical systems
commercially used produced a superabundance of stray light.

It was at this stage of the art that Mr. Oakley of Dupont was asked
to work out some fine-grain materials for the talking-book project.
The requirements laid down were as unique as they were simple:

"Use every precaution to keep the grain fine — a Lippman type
emulsion is the sort of thing we need." With this all-inclusive re-
quirement as a guide, Drs. V. B. Sease, D. R. White, and others of the
Dupont research group quietly went to work.

The details of the work are too long to report here; for a period of
a year or more Mr. Maurer made recordings every week, including a
number of recordings of Walter Damrosch's Musical Appreciation
Hour. Often during the year the author listened to impromptu re-
corded concerts when we would compare the quality of the older
talking-book recordings with that of the newer ones.

The quality was somewhat better than the best disk records of that
time; it was marred far more by the microphonic ping of the 224 tube
in one of the low-level amplifier stages than by any "ground noise"
or distortion evident in the speech of Dr. Damrosch, in the music of
his illustrative piano, or in the orchestral performance that followed.
The recordings as reproduced were especially free of noise and dis-
tortion.

What is especially significant is that these recordings utilized film
running at 45 feet per minute with a maximum sound-track width of
only 2 mils as compared with 60 mils for standard 16-mm tracks.
There were more than 300 sound-tracks on a print of one of these
films that the writer gave to Col. M. E. Gillette in 1934 for his sample
collection.

Experience with the talking book sharply accentuated the impor-
tance of fine-grain film and its processing. In a special series of fine-
grain tests in which distilled water was used instead of water
filtered and cleaned in the manner typical of commerical laboratories
at the time, noise was reduced some 10 db. Even today a reduction

380 W. H. OFFENHAUSER, JR. [J. S. M. P. E.

of 10 db in noise is something to be sought for; if water cleanliness
will do it, every effort should be made to keep the water clean. (Dirty
water is still a serious problem in commercial processing.)

The quality of the talking-book records was remarkable for the
time; most commercial laboratories processing 16-mm release prints
today would be more than pleased with equal quality. Contemporary
production prints do not yet equal those old records in quality; the
reason for the technical superiority of the old records is quite simple;
the resolving power of the special 1931 film was 100 to 110 lines per
millimeter, about double that of the ordinary positive used by most
laboratories today.

Fine-Grain Release-Print Material: Dupont 610. — With such a
background as this, it was only logical for Precision Film Laboratories
to grasp the earliest opportunity to use fine-grain materials in 16-mm.
When Dupont began to market their 610 emulsion several years ago,
it was considered most desirable to adapt the methods to be
used to the available material; it was felt that commercial benefit
could be derived from the excellent basic work accomplished in 1930
and 1931. Comparison was possible only between Dupont fine-grain
610 and ordinary positive materials (there were no other fine-grain
materials on the market). Within a year after the first trials of this
material, our Laboratory dropped ordinary positive altogether and
has processed none since.

Dupont 605. — For well over a year after the first tests with Dupont
610, no film manufacturer other than Dupont offered a 16-mm fine-
grain release print material. During this interval the film was being
constantly improved, and later Dupont 605 was evolved. This new
material proved even better than its predecessor and, since its ad-
vantages were outstanding, our Laboratory standardized on it as the
one and only raw film for release print purposes.

Today's Status — Conditions of Use. — For procedure simplification
and for best quality and maximal uniformity of product, our Labora-
tory still uses one release positive material: Dupont 605. This ma-
terial satisfies the commercial requirements with regard to operating
costs, and, in addition, to such technical requirements as image tone,
photographic scale, resolving power, and graininess, as well as a very
desirable hardness of emulsion that makes "protective coatings" and
similar treatment unnecessary for prints projected in machines that
are kept in good repair.

To get the most out of this excellent fine-gram release print ma-

Nov., 1943] APPLICATION OF FINE-GRAIN FILM 381

terial, all release prints are developed at one developing time. All
printers are of the step-contact type; these seem to give best image
definition. For uniformity, all printers are of the same type; all use
the same type of lamp as a light-source, all run at the same speed, and
all will print any dupe negative (made in our Laboratory) on the
same single printer light. Within the past two years we have found no
outstanding attributes of any other fine-grain release positive ma-
terials to justify altering this procedure.

In practice, only the compensations for the batch-to-batch varia-
tions of sensitometric characteristics are necessary to keep the process
well under control. To develop this fine-grain film properly necessi-
tated an increase in developer concentration of about one-third together
with an increase in rhodol (the increase is more than two to one) and
a reduction in the bromide of about one- third. The reference formula
is the Eastman D-16.

With the experience of 1931 in regard to the talking-book project
in mind, special pains are taken to filter and clean all water, to main-
tain temperature control, and last but not least, to control the clean-
liness, the humidity, and the temperature of the drybox air. It would
seem futile to go through all the motions of control that have been
indicated, and then spoil the good work by imbedding muck from
dirty chemical baths or wash water, and by forcibly blowing dust and
other dirt particles right into the emulsion during the drying process.
A 10-db reduction in noise which can be achieved by cleanliness is
well worth striving to obtain. As has been explained in some detail
in a previous paper,1 great care and attention are given to proper fixing
and drying. Film may be taken directly from the developing machine
take-up for immediate projection on the Bell & Howell Utility pro-
jectors that are used for inspection. No "preservative" is needed to
"ease" the film through the projector; the film is not "green."

The Duplicate Negative. — The positive print is held within quite
narrow sensitometric limits; these limits are predetermined by the
characteristics of the film itself, by the developing machine, and by
the machinery used to expose the film. To produce a release print in
the manner described requires an "evened-out" duplicate negative
that is quite uniform; the characteristics of this duplicate negative
are the key to the methods employed.

As in the case of the release positive material, the first step is to
select the one most desirable duplicate negative raw film; the ma-
terial with the highest resolving power and the most suitable scale

382 W. H. OFFENHAUSER, JR. tf. s. M. P. E.

and gamma. In this case the choice was Eastman 5203. The rated
resolving power is 110 lines per mm in an SD-21 developer at a
lib control gamma of 0.65 (which represents a developing time of 6
minutes). To make fine-grain prints of proper contrast from re-
versal or Kodachrome originals with this material for the inter-
mediate duplicate negative requires a smaller lib control gamma
(under our conditions) than is specified in the Eastman data. The
first step was to determine what the control gamma should be for
an "average" reversal or Kodachrome and to make adjustments in
the developer bath and elsewhere so that our regular step-contact
printers with their 20-light scales may be used in making these dupe
negatives. As before, the machines were the same, the lamps were
the same; obviously the juggling had to be done with the de-
veloper bath. We made one slight change; since there was plenty
of exposure available, a filter was introduced to limit the exposing
light to wavelengths shorter than 5000 Angstroms. This helped to
reduce the contrast and improve the definition and graininess of the
dupe negative. (EK 5203 is panchromatic.)

Timing. — We had observed in printing a black-and-white duplicate
negative from a Kodachrome original, that the timing was quite
similar to that used in printing a Kodachrome duplicate from the
same original. If the contrast of the finished products were supposed
to be the same, there would seem to be little reason why it should not
be possible to make the timing of them identical. This proved to be
practicable as a commercial procedure ; today the timing of a Koda-
chrome original for black-and-white prints is identical to its timing
for Kodachrome duplicates. When this procedure was first tried
commercially, slight readjustments in dupe negative developing were
required. It may be interesting to know that the developer bath
for duplicate negatives is used also for original negative; the only
difference is an appreciably longer developing time for original
negative. The amount of 16-mm negative in use is very small;
negative is not used today in any project where a large number of
prints is required.

Developing the Dupe Negative. — The bath for the dupe negative
is such as to produce the desired gamma with a developing time of 3
to 4 minutes. The lib control gamma for EK 5203 under our condi-
tions is in the range 0.35 to 0.40, slightly lower than that of usual
developers. Accurate sensitometric control is a "must"; experience
over a long period points out quite forcibly that no timer can properly

Nov., 1943] APPLICATION OF FINE-GRAIN FILM 383

time a film for printing unless the process is well "tied down." When
we first tried to make prints from dupe negatives, it did not take long
to recognize that timing a duplicate negative for a print usually
resulted in a poorer print than a one-light print from the same dupe
negative. Obviously the error was in making the dupe negative from
the original; the proper correction of the error is correction at the
source: a new dupe negative. The resulting technique — with all
timing in making the dupe negative and one-light printing of the
dupe for making the release prints — would seem to be almost ideal
for making highest-quality fine-grain black-and-white prints in large
quantity with greatest uniformity.

16-Mm Prints from 35-Mm Negatives. — When it is necessary to
make good fine-grain 16-mm prints from 35-mm negatives, our
Laboratory prefers a low positive gamma (1.40) yellow-dyed fine-
grain untimed 35-mm master positive on such film as Eastman 1365;
the one-light master positive is actually much better than the usual
mis-timed copy. It so happens that such a master positive may be
timed in our plant in making a 16-mm dupe negative in exactly the
same way and using the identical timing scale as that for Koda-
chrome or reversal 16-mm originals. Black-and-white fine-grain
release prints made in this way result in excellent gradation, really
fine-grain, and a definition and softness that is unknown in direct
reduction printing from 35-mm original negatives. (Step picture
printing is used throughout.)

Most commercial reduction printers run at too high speed to
provide sufficient exposure for fine-grain film; if these printers are
slowed down to speeds that will provide adequate exposure, the
resulting print is too contrasty for usual positive developers. For
direct reduction printing on fine-grain ] 6-mm films, 35-mm original
picture negatives are made to far-too-high gammas for successful use.

SOUND

So far this paper has dealt only with the picture phase of the
printing problem; a paper that would do justice to the subject must
emphasize sound for the reason that sound can be said to have
started it all. To acquire the proper perspective, it is necessary to
digress somewhat in considering the subject. It is a well known
experimental design trick for an investigator to make scale models
of the device he is studying. If the device is something big such as
a Mars flying boat or a new super-dreadnaught, he makes small

384 W. H. OFFENHAUSER, JR. [J. S. M. P. E.

models that are convenient to study in a miniature wind-tunnel or
test-tank. If the device is something small such as a high-quality
cutter for disk records, he makes large models so that the action of
the various moving members may be studied in more convenient
fashion. Knowing the characteristics of the system under investi-
gation, it is possible to predict the performance of the full-scale
device from the knowledge of the performance of the made-to-scale
model.

In a sense, the fine-grain application problem was similar in its
first approximations especially. If 35-mm could tolerate a resolving
power of so many lines per mm, 16-mm would require 2l/2 times that
figure. If 35-mm could tolerate so many pounds of muck per million
gallons of water, 16-mm could tolerate not more than 1/&6 that
amount. If 35-mm could tolerate so many pounds of dirt per million
cubic feet of air used for drying, 16-mm could tolerate not more than
1/z.& that amount. This proved a good starting point.

The 16-Mm Sound Negative. — As in all cases of proportional scalar
design, non-linear relationships were found: in simpler language,
"bugs." One of the worst of these was the poor resolving power
of film materials used for 35-mm sound recording. The resolving
power available was too low for 16-mm; only x/2.5 the proportional
requirement. There was little hope in conventional films; sub-
stantial increases in resolving power resulted in requirements of
exposure considerably beyond what could be hoped for in the exposing
ability of a 6-volt 1 -ampere lamp. At our request, Agfa made a
yellow-dyed film (now known commercially as Agfa type 250 high-
resolving-power sound-recording film) which worked quite well
when exposed through a Jena BG-12 filter.2 The harmonic distortion
in the negative was reduced far below that in the usual 35-mm ultra-
violet stocks with ultraviolet exposure; in a variable-area negative
of density 1.5, for instance, the harmonic distortion of an 85 per cent
modulated 400-cycle wave was under 1 per cent, whereas a distortion
of about 8 per cent was common in 16-mm ultraviolet negatives.
It is well to point out that for more than three years no competitor
attempted to market a comparable film ; it appeared that no competi-
tor thought it worth while.

Commercial production experience with Agfa 250 for 16-mm
sound negatives and Dupont 605 for release prints (variable-area
recording) produced a series of incidents indicating that further
progress would have to be made without any further attempt to rely

Nov., 1943] APPLICATION OF FINE-GRAIN FILM 385

on previous 35-mm experience. Prints of 400-cycle 85 per cent
modulated recordings were possible with quite consistent rms har-
monic distortion less than 2 per cent. Intermediation tests of
6000 — 400 cycles and 4000 — 400 cycles gave strange results when
checked with the harmonic distortion results. It appeared that we
had run into a new breed of "bug" with which the industry seems
to have had no previous experience.

One odd phenomenon of this new breed is worth mentioning.
Suppose that a conventional sound negative is recorded in which
there is a voice together with a musical background. By making
a print in one manner, the subjective level of the music is raised
with respect to the voice; by making a print in another manner,
the subjective level of the music is lowered with respect to the
voice. Both prints, when compared, are quite "clean" by today's
highest commercial standards, yet the difference in subjective level
of the music referred to that of the voice seems as much as 10 db in
the two prints. If this phenomenon were to occur in Hollywood,
it would certainly lead to much disagreement between a re-recording
mixer man and the director if either should depend upon the sound
from the monitor horn at the time the take was actually made.

This phenomenon has its caution lights; the character of the dis-
tortion is audibly different in one kind of print from that in the other.
Unfortunately we have found no magic formula to provide an un-
equivocal answer as to how a print shall be processed; neither inter-
modulation nor harmonic distortion tests alone are reliable. As
George Friedl used to phrase it at our Standards Committee meet-
ings, "It is a matter of how we prefer to have our sound distorted."

A common characteristic of distortion in improperly processed
35-mm variable-density prints is harmonic distortion, yet with 16-mm
fine-grain variable-density prints we have encountered some out-
standing examples of whistling sibilant distortion that are ordinarily
associated with variable-area records. Similarly, while the common
distortion characteristic of variable-area 35-mm records that are
improperly processed is envelope distortion, we have encountered
some outstanding examples of raspiness due to harmonic distortion
with little evidence of envelope distortion. With the materials
described in this paper, however, both envelope distortion and
harmonic distortion are at a minimum, and are somewhat below the
distortion levels in current 35-mm feature prints released to theaters.

It is no longer possible to classify a sound recording as variable-

386 W. H. OFFENHAUSER, JR. [j. s. M. P. E.

area or as variable-density merely by the character of the most
apparent audible distortion. If noise levels and distortion levels
are to be further reduced, as they should be in the near future, new
techniques will have to be evolved; they may take into account even
the character of the sound to be recorded. It is no longer possible
to specify the optimal density of a print from a sound negative by
merely applying a rule of thumb ; a specification that requires such
material or a laboratory that produces it will soon show all too
plainly that the industry has been accelerating rapidly out of the
rule-of-thumb era.

16-Mm Sound Negative Materials. — Within the past year, Eastman
Kodak has released EK 5372, a blue-dyed film which is functionally
similar to Agfa 250. EK 5372 is definitely "faster" than Agfa 250
when exposed in a Maurer 16-mm sound recorder. For that reason
it is convenient to use, but sufficient data are not yet available to
determine whether the increase in speed is not gained at the expense
of too great a loss of resolving power. For ordinary purposes, the
practical differences do not seem large.

Conclusion. — In the earlier part of this paper, it was pointed out
that a desirable "ideal" would be to use materials of resolving power
of I37l/z lines per mm or greater. Under practical conditions of
operation, it is likely that our Laboratory approaches this figure
with the duplicate negatives. The release-print material falls some-
what short, although the conditions realized in practice are better
than the published data. These materials and the technique of
handling them result in 16-mm print quality of the very highest
commercial standards. Film processed in this manner is more than
adequate for picture projection with the best 16-mm lenses in the
best 16-mm projectors. With regard to sound, the significant
improvement resulting from the engineered use of fine-grain materials
is not so much the extension of the frequency range (together with
the reduction in noise, hush-hush, and other equally obvious and
readily recognized factors) as the reduction of distortion to levels
far below those expected from "scale-model" considerations of 35-mm
apparatus and materials.

There is plenty of work to be done to boost the quality level of an
"average" 16-mm performance. Today we are using film materials
whose resolving power is comparable with that of the lenses of better-
grade projectors : 80 lines per mm. Already there has been signifi-
cant clamor for revision of this figure upward although it was con-

Nov., 1943] APPLICATION OF FINE-GRAIN FILM 387

sidered satisfactory only a year and a half ago. Materials with
resolving power of 100 lines per mm were available in 1931;
150-lines-per-mm material is available now. The technique of
manufacture of the latter material is fairly well known ; the problem
is to prepare to process this material commercially and to bring the
price to lower levels by making the use of such material the rule
rather than the exception. This, it seems, is the next hurdle for
progressive laboratories to jump regardless of whether they process
100,000 feet or 100,000,000 feet per year.

Good film can be obtained now; the film manufacturers are
prepared to help any laboratory that is interested by providing in-
formation as to the highest-resolving-power materials they sell and
the manner of effectively using them. The major step that is
missing, and which can be readily taken if there is a serious and
honest interest in quality, is the requirement in all Government
specifications that any release print will be rejected if in test under
actual conditions of use it shows less than 100 lines per mm; any
duplicate negative will be rejected if in test under actual conditions
it shows less than 110 lines per mm; and any master positive will be
rejected if in test under actual conditions it shows less than 150 lines
per mm. Any test to be valid shall be a continuous part of the film
under test; it shall not be removed from the film. Rejection shall
result without further inspection if the specified test-strip does not
appear on the end of each film.

These requirements on resolving power will make an excellent
starting point; once they have been included in specifications, and
rigid and thorough 100 per cent inspection is instituted to assure that
the specification is being met, the big step in the direction of quality
for 16-mm release prints will have been taken.

REFERENCES

1 OFFENHAUSER, W. H., JR.: "The 16-Mm Commercial Film Laboratory,"
J. Soc. Mot. Pict. Eng., XLI (Aug., 1943), p. 157.

*MAURER, J. A.: "The Present Technical Status of 16-Mm Sound-Film,"
/. Soc. Mot. Pict. Eng., XXXIII (Sept., 1939), p. 315.

8 OFFENHAUSER, W. H., JR., AND HARGROVE, F. H.: "Some Industrial Ap-
plications of Current 16-Mm Sound Motion Picture Equipment," /. Soc. Mot.
Pict. Eng., XXXIV (Feb., 1940), p: 156.

4 Report of the Committee on Non-Theatrical Equipment: "Recommended
Procedure and Equipment Specifications for Educational 16-Mm Projection,"
J. Soc. Mot. Pict. Eng., XXXVH (July, 1941), p. 22.

388 W. H. OFFENHAUSER, JR.

* STEPHENS, R. E., "Optical and Mechanical Characteristics of 16-Mm Mo-
tion Picture Projectors," Bur. Stand. Circular C437 (June, 1942).

• SNYDER, W. F., "Acoustic Performance of 16-Mm Sound Motion Picture
Projectors," Bur. Stand. Circular C439 (July, 1942).

7 OFFENHAUSER, W. H., JR.: "A Review of the Question of 16-Mm Emulsion
Position," /. Soc. Mot. Pict. Eng., XXXIX (Aug., 1942), p. 130.

8 "Eastman Motion Picture Films for Professional Use," Eastman Kodak
Company (Rochester, N. Y.), 1942.

9 MAURER, J. A.: "Commercial Motion Picture Production with 16-Mm
Equipment," /. Soc. Mot. Pict. Eng., XXXV (Nov., 1940), p. 437.

10 OLSON, H. F.: "Extending the Range of Acoustic Reproducers," Proc. Radio
Club of Am., Vol. 18, No. 1 (Jan. 1941).

PLANNING FOR 16-MM PRODUCTION*
RUSSELL C. HOLSLAG**

Summary. — The paper discusses production of 16-mm "expository" films — those
which explain or instruct. The most important factor involved is the advance plan-
ning of an adequate presentation of the subject matter. A direct, simple method of
production planning has been evolved and is described, pointing out pitfalls which the
beginner should avoid. A shooting-script form, which serves the producer as a com-
bined scenario, shooting script, and editing reference, is described and illustrated.
Experience indicates that the teacher or expert who is to guide the production of a
training film should give his particular attention to building up a concept; avoiding
overextended commentation; having the visual demonstration coincide with the sound-
track explanation; showing no action that is unexplained, or no explanation un-
accompanied by action; timing the delivery of the commentation; using the full power
of the camera; and to treating the audience as an individual novice about to receive
instructions through motion pictures.

The term "production" is all-inclusive, and it is not the purpose
of this paper to deal with the many aspects of dramatic production or
with the planning of films intended for entertainment purposes. The
type of production to be discussed is the one in which 16 mm is now
especially called upon to perform — that of rapidly turning out films
which might be called "expository," films which explain or instruct.

Since there is so much of this kind of film training to be done, we
find that the task of planning such films must often be assumed by
those who may be thoroughly acquainted with the details of the
subject matter of the film to be made, but who may not be so well
acquainted with the methods of planning and presentation that will
make an effective motion picture. As a matter of fact, the inevitable
growth of the expository film will make it necessary for the teacher or
expert in any given subject to produce the film, rather than the
motion picture expert. The educator will therefore find it necessary
to learn enough about the needs of the film medium to present this
instruction effectively, just as he must be able to describe his subject
logically and clearly in writing if he wishes to write a text-book.
And as the writer of a practical text-book need not, and usually does

* Presented at the 1943 Spring Meeting at New York.
** J. A. Maurer, Inc., New York.

389

390 R. C. HOLSLAG [J. S. M. P. E.

not, indulge in colorful word painting and imaginative prose to make
his message attractive, the practical producer of teaching films need
not feel himself called upon to adopt the dramatic devices that be-
long to the entertainment field.

Confronted by a motion picture project, the specialist with a thor-
ough knowledge of his subject may be at a loss as to how to organize
this knowledge along lines which will (1) enable the actual shooting
to be carried out with a minimum of lost motion and waste of time;
(2) arrange the material so that the cutting and editing do not present
any unusual problems ; and (3) include only the material necessary to
produce a direct, straightforward result.

Since thoroughly adequate results, both in picture and sound, may
now be obtained with existing 16 -mm apparatus by any intelligent
person who will take the trouble to familiarize himself with the neces-
sary instructions, it follows that the most important factor involved is
really the advance planning of an adequate presentation of the
subject matter. Through a great deal of direct experience with this
type of user of 16-mm apparatus, and through a general review of
what seems most in need of emphasis, there has been evolved what is
believed to be a direct, simple method of production planning. If
this method is carefully followed, experience has shown that results
in the production of expository films are quite adequate, even when
they are made by those who have not had any particular experience
with the motion picture as a medium of exposition.

The planning schedule, as devised, assumes the use of a sound com-
mentary to accompany the visual presentation of the subject. Be-
cause of the fact that there are very few occasions where spot-re-
corded sound is necessary to add to the actual teaching value of the
film, the plan makes provision generally for the later addition of a
proper commentary after the film has been edited and the breaks
smoothed out. Spot-recorded sound can in many cases add to the
dramatic value of the film, but this is generally apart from its straight
training value.

Many who are called upon to plan their own specialized training
motion pictures for the first time have only the model of theatrical
motion pictures as precedents which tend to confuse the issue. In
view of the pressing need for good training motion pictures at the
present crucial time, we may safely assume that our pictures will be
given attention by any audience which hopes to benefit from it, with-
out unnecessary dramatic devices. This applies to fancy transitions,
trick wipes, mood music, elaborate introductions and conclusions,

Nov., 1943] PLANNING FOR 16-MM PRODUCTION 391

entertaining animation sequences and other methods used in theat-
rical or persuasion films to compel the attention. In view of the
seriousness of the situation in which training films are now called
upon to serve, it is felt that they need not entertain any more than
an instruction book entertains.

Another tendency which should be avoided in advance is over-
elaboration and its corollary, the attempt to include too much ma-
terial in each film unit of the subject under consideration. This is
generally the result of the specialist's great familiarity with his sub-
ject; that is, he is apt to assume that many points of the explanation
are obvious and so need not be emphasized. This is a particularly
dangerous conception in the case of a motion picture presentation,
because a given action should always be followed through to its con-
clusion to avoid a jumpy effect. If this principle is not observed,
the action when photographed may leave many fundamental points
unexplained. The result will be an attempt to supply the missing
explanation by means of the commentation alone — an attempt that
will usually leave the announcer breathless and the audience be-
wildered. The only real remedy is replanning and retaking.

Another pitfall to be avoided is often brought about by the plan-
ner's literary ability. Many authorities can write clear, lucid ex-
planations of their subjects and are apt to feel that they can create
a successful training film by writing a good literary commentary,
letting the picture simply trail along at its heels. This, of course,
does not take into account the effective combination of action and
explanation of which the motion picture is capable. In addition,
there is always the danger of writing too much with the result that the
action has to take place too quickly to keep up with the rapid ex-
planation. On the other hand, a companion danger occurs when it is
planned to photograph the operation in advance in as many aspects
as possible; then to edit them and to try to fit them into a smooth-
running commentary. This nearly always results in action which is
either too short or too long for the proper flow of explanation.

In practice the best results are gained when the visual impression
is created coincidentally with the explanation or comment, the latter
not involved or verbose but simply describing the action that is pro-
ceeding at the moment. Keeping this principle in mind is a real aid
in planning both the visible and audible components of a training
film together, thus making it fulfill a direct purpose. It is also a
great help in overcoming the temptation to be too literary in writing
the commentation.

392

R. C. HOLSLAG

U. S. M. P. E.

One of the very practical methods for sketching out the plan of an
instructional film is to make a verbatim transcript of the explanation,
and resulting questions and answers, involved when a beginner is
actually introduced to a new process by an instructor. This would
apply with equal force to almost any subject, from the handling of a
hammer and chisel to the assembly of a complicated mechanism.
The information given, the questions asked, and the interval of time
between questions provide a valuable index to the amount of material
that should be covered in a given time on the screen.

As to the mechanical transfer of the idea material to its most con-
venient form for the preparation of picture and sound-track, there
has been developed a simple form of "shooting script" which at least
has proved successful in a number of cases where training film had to
be turned out speedily. It serves as a combined scenario, shooting
script, and editing reference. By a simple understanding of the points

FILM TITLE:

SUBJECT:

SCENE
NO.

ACTION

FOOTA6E
FOR S<SJND

FOOT**

SHOT

COMMENTATION

NOTES

LS Opera tor pi aces
~$hel in water, I****
~to*qs

H^ coo2 it su<JJe-n2y by

M&J MO^I'I^O "&he

~~~piece areurtd en -the
water. Inspect once
or twice. Jt rfw&se
at e*4 a f scene

Notice that ^ewove the
piece around in the,
waiter £16 it. cools. This
prevents -Me format/**
cf steam bubbles which
"miarit cause uneven
Cc&Snf.

^tfn'"-f

FIG. 1.

already noted, together with a thorough knowledge of the subject
to be recorded, a practical and direct shooting plan can be evolved by
filling in each of the columns provided in the form given. Fig. 1
shows a sample form typically filled in.

The headings are self-explanatory. Each separate scene — that is,
the action photographed during the interval between each start and
stop of the camera — is numbered in the left-hand column. The
action is described in the second column. The narrow column
headed Min. Footage for Sound denotes the footage necessary to
obtain in the take to permit the full sound commentation for that
scene to be added later. The footage shown in the next column is
filled in immediately after the take and must not be less than that
shown in the previous column. In a picture planned along the lines
recommended, it is usually more. The actual wording of the com-
mentation is found in the next column. This, of course, will be added
after the picture editing is completed. If it is necessary to have any

Nov., 1943] PLANNING FOR 16-MM PRODUCTION 393

given point in the action match with a given word in the commentation,
it will help to have the words read aloud during the rehearsal and also
during the take. The footage needed for a given number of average
words in a commentation may be calculated roughly by allotting about
three words to each foot of film (!2/3 seconds at a film speed of 24
frames per second). In the average 400-ft film unit there are ap-
proximately 40 to 50 scenes.

The final column headed Notes will take care of any special data
that actual shooting conditions may bring about. This will also
provide space for notations on retakes. In general, at least two takes
should be made of every scene, and preferably three. This usually
seems unnecessary to the film maker without much experience, but it
is the best form of insurance against retakes which otherwise may
be found lacking only after the editing is completed. Each scene
should be carefully slated and, in editing, the first rough draft of the fin-
ished picture should be made from a work-print, leaving the slate iden-
tifications in the film until all final editing decisions have been made.

The shooting script form (Fig. 1) should be typed or multigraphed
so that the long dimension of the sheet is horizontal. Multiple
copies should be provided and copies in active use should be bound.
A copy is given to the cameraman for study and actual use, a copy
goes to the supervisor of production, while other copies, of course,
are kept for records. Experience in this kind of shooting has shown
that it is advisable, as far as possible, to take each scene in the se-
quence in which it is shown on the script. With large studio pro-
duction facilities, it is feasible to group together all convenient scenes,
regardless of their sequence. But for simple training films not in-
volving extended locations, less confusion will result if the scenes are
shot in a straightforward order, one by one.

With this form as a guide, the specialist producer is now ready to
work out his script in a logical form. Keeping in mind the desir-
ability of a straightforward, direct approach and avoiding the pit-
falls outlined, he will select a portion of his subject and proceed to fill
in a trial script to ascertain its probable length. It would be well to
confine a first attempt to a subject within the length of a 400-ft unit
which will be found to average about fifty scenes.

In visualizing the subject for motion picture presentation, the film
planner can proceed most rapidly by imagining a situation in which he
is actually showing a beginner how to work with the material illus-
trated. He must conceive his screen audience as the embodiment of
the beginner. Since most specialist teachers have had this experi-

394 R. C. HOLSLAG

ence, this would seem the best introduction to the method of presen-
tation. Experience of this kind will indicate the questions that will
be asked and also what parts of the subject are to be emphasized.

In planning a logical sequence of scenes with the above in mind,
the arranger should always keep before him the inherent flexibility of
the motion picture camera as to viewpoint. The camera brings to
the entire audience the visual impression gained by a single indi-
vidual who must be imagined as receiving the instruction. Just as
this individual would have complete freedom to look at the subject
closely, or to gain an impression of the whole thing by stepping back,
so the camera can emphasize or generalize by means of the long shot
and the close-up. As the individual's attention is constantly di-
rected to the various details, the camera may also record a constant
variety of shots as the explanation proceeds.

This will be found a satisfactory method of estimating lengths of
scenes, changes of viewpoint, and the logical progress of one scene to
the next, which is called continuity. No claim is made that this
planning process will give an automatic knowledge of the scope and
limitations of the camera work itself, for the planner must consult his
cameraman at all times and on all points to find out what the camera
can and cannot do. In general, however, he will be agreeably sur-
prised to learn that the camera can show plainly everything a beginner
can see, and he will find, in addition, that the camera can often go
beyond this and can present things that are ordinarily unseen, even
to abstract conceptions.

In brief, experience indicates that the teacher or expert who is to
guide the production of a training film should give his particular at-
tention to the following points :

(1) Do not omit any important step in building up a concept, no
matter how simple.

(2) Do not write a commentation that is overextended.

(3) Have the visual demonstration coincide in all cases with the
sound-track explanation.

(4) Show no important action that is unexplained, or no explana-
tion unaccompanied by action.

(5) Time the delivery of the commentation carefully in advance
while mentally or actually rehearsing the action.

(6) Take full advantage of the concentrating power of the camera
through the use of closeups.

(7) Consider the audience as an individual who is to receive in-
structions through the film in the same way as a beginner.

PRECISION RECORDING INSTRUMENT FOR MEASURING

FILM WIDTH*

S. C. CORONITI AND H. SCOTT BALDWIN**

Summary. — The paper discusses a mechanical electronic device which con-
tinuously measures the width of film to an accuracy of 0.002 mm. The basic circuit is
quartz oscillator having a L.C. circuit which is slightly detuned from the resonant fre-
quency. The percentage detuning gives a measure of the film width. Curve shows
that for a film variation of 0.250 mm the relationship between film width and measur-
able current is linear. An inexpensive 0-1 milliammeter can be used without sacri-
ficing accuracy,

Precise measurement of film width is of direct interest to cine-
matographers, laboratory technicians, and projectionists only so far
as it assists the equipment designer and the film manufacturer to
provide them with materials that will give optimum performance at
all times. With standard equipment and film of standard dimensions,
the creative branches of the film industry can direct their energies
toward production of the finest pictures, unimpeded by technical
problems that were inescapable some years ago.

Motion pictures, especially 16-mm films in which minor dimen-
sional variations are of relatively greater importance than in 35-mm
films, are being used increasingly for scientific investigation and the
automatic recording of data in industrial operations. In such work,
problems in connection with film steadiness and dimensional char-
acteristics, which would not arise in normal motion picture pro-
duction, sometimes assume an importance that calls for dimensional
measurements of the utmost accuracy.

The exact control of width during manufacture of 35-mm, 16-mm,
and 8-mm film has always been a problem in the photographic in-
dustry. Obviously, before any effective measures for control can be
adopted, it must be possible to measure width of the film most ac-
curately to determine the nature and extent of variations which, in
turn, serve as clues to factors causing deviations from the norm.

* Presented at the 1942 Fall Meeting at New York.
** Agfa Ansco, Binghamton, N. Y.

395

396 S. C. CORONITI AND H. S. BALDWIN [j. s. M. p. E.

All common types of motion picture film consist of an emulsion
coated on a thin cellulose ester base (approx. 0.005 inch) . The material
is extremely flexible at this thickness, and this flexibility virtually
precludes the usual methods of measuring, as with the micrometer or
minimeter, if measurements are to have the desired precision. Added
to the difficulty presented by the physical characteristics of film
itself are the very small tolerances to be maintained. Table I lists
the SMPE Standards and allowable tolerances for cutting 35-mm,
16-mm, and 8-mm raw stock.

TABLE I

Mm. Inches

35-mm 35-mm + 0.000 1.378 + 0.000

- 0.05 - 0.002
16-mm 16-mm + 0.00 0.630 + 0.000

- 0.05 - 0.002
8-mm 8-mm + 0.00 0.315 + 0.000

- 0.08 - 0.003

The average variation that can be allowed, therefore, is 0.002 inch
or 0.07 mm.

Other points to be considered in controlling the width of films are
the quantity and the lengths involved. Nearly all 35-mm films are
furnished in 1000-ft rolls, and 16-mm films are available in the same
length, although 400-ft rolls are more common. Eight-mm films are
furnished in shorter lengths, but regardless of length, every roll must
be controlled with accuracy to be sure that the width does not show
variations in excess of allowable tolerances. From these considera-
tions, the need for an instrument that will quickly and accurately
measure the width throughout long lengths of film will be obvious.

Present Method of Measuring. — At the present time there are two
general methods used in measuring the width of motion picture
films: one utilizing optical instruments, and the other requiring
mechanical instruments of rather familiar type. Of the optical
instruments for precision measurement, the Zeiss Comparator and
that made by Jones & Lamson are most familiar. In construction,
both these instruments are accurate to the fourth place in millimeters,
but owing to practical considerations, this accuracy is not realized
in film width measurements. In fact, for the purpose, optical
instruments present disadvantages in respect to time consumed and
continuity of measurement. For accuracy, each section of film must

Nov., 1943] INSTRUMENT FOR MEASURING FILM WIDTH 397

be cut from the roll and adjusted on the viewing stage before
measurement, the entire operation requiring approximately five
minutes. It is not possible 'to read width variations continuously
throughout the entire roll and the time required for individual read-
ings becomes a major factor.

For measuring film width by mechanical means, the micrometer
or the dial-gauge type of instrument may be used, but neither is very
satisfactory. The former can not be used to obtain precise measure-
ments because pressure against edges of the film, required for an
accurate reading, is great enough to make the film buckle, and the
time required for measurement is as great as with the optical in-
struments. Use of the dial-gauge instrument involves also consider-
able pressure against edges of the film, and mechanical amplification
of movement imparted by variations in film width is not sufficiently
even to give readings of greatest accuracy. Adequate maintenance
of these instruments presents also a definite problem in routine pro-
duction control.

Consideration of the problems that arise in using conventional
optical or mechanical instruments warrants the following con-
clusions :

(1) Dependence upon operative skill for accurate positioning of the specimen
makes measurement tedious and frequently inaccurate.

(2) Instruments requiring relatively forceful contact with the object to be
measured, for accurate readings, are unsuitable for measuring fragile, thin, or very
flexible materials.

(5) Amplification of movement imparted to a measuring instrument by means
of mechanical linkage is seldom sufficiently reliable for the utmost precision, and
maintenance is a considerable problem in routine production work.

(4) Continuous measurement of the width or thickness of an unbroken strip of
material, with extreme accuracy, great rapidity, and with automatic recording of
dimensional changes, has hitherto been but a dream of production engineers, with-
out hope of realization by use of existing instruments.

Assuming that the specimen could be positioned for measurement
in reproducible manner, without skill on the part of the operator,
and that very light contact with the gauge would suffice for measure-
ments of the greatest precision, it is apparent that an instrument
actuated by mechanical contact with the specimen would be most
convenient for determining the exact width or thickness of a motion
picture film. Although physical contact between the film and the
gauge does simplify the use of an instrument, the micrometer prin-
ciple must be abandoned if rapid action is desired and mechanical

398 S. C. CORONITI AND H. S. BALDWIN [j. s. M. P. E.

amplification is not entirely reliable for accurate work. With these
points in mind, certain fundamental characteristics of a suitable
instrument may be listed as follows :

(1) Film to be in physical contact with guide for positioning specimen, with
physical contact between film and variable member of the gauge.

(2} Linkage between the variable member of the gauge and the indicator is to be
practically frictionless and free from inertia or irregularity of action at any posi-
tion within the measuring range of the instrument.

(5) Mechanical construction is to be simple, rugged, needful of minimum main-
tenance, and not easily damaged.

Following a thorough study of the problem and the principles and
limitations of available measuring instruments, all three of the es-
sential characteristics listed above have been incorporated in a new
electronic film-width gauge, characterized by simple mechanical
construction and a stable electrical circuit, which eliminates mechani-
cal linkages by electronic amplification. This allows the con-
tinuous automatic measurement and recording of film width, rapidly
and with precision heretofore attainable only by skilled operators
using the most accurate optical instruments.

The electronic width-gauge gives measurements in agreement with
test-blocks and with the stereo comparator, but readings are
reproducible within 0.002 mm, a degree of accuracy somewhat beyond
that attained by operators using the stereo comparator. With minor
changes in construction, the electronic width-gauge can be adapted
to give width or thickness measurements of requisite precision for
many other applications in science and industry.

The essential mechanical element of the film- width gauge is a small
lever, about 2 inches long, swinging on a bearing about one-third
the distance below the upper end. At the upper end of the lever, a
rounded surface presses lightly against one edge of the film as it
passes through the gauge. If the film becomes wider, the upper end
of the lever is pushed outward, and since this is above the fulcrum,
the lower end of the lever swings inward. As the lever swings, a
metal disk at the lower end moves nearer to, or farther from, a similar
disk which is fixed and immovable. These two metal plates never
actually touch one another, but as the distance between them varies
with variation of film width, they actually constitute a variable
condenser.

With change of film width there is a change in capacitance of the
variable condenser, and this change is amplified electronically, giving

Nov., 1943] INSTRUMENT FOR MEASURING FILM WIDTH 399

instantly a direct reading or recording of film width in millimeters.
Thus, with but one moving part in the actual measuring mechanism,
variations of film width are measured in a fraction of a second, and
the most minute changes are amplified to a degree allowing clear
and easy reading, without injury to film from pressure of the mecha-
nism.

Mechanical Construction. — Fig. 1 is an oblique view of the electronic
width gauge, showing the important mechanical features of design.
Film 1 passes from the feed roll, under guide-roller 2 through the
measuring head under the second guide-roller 3, and to the take-up
roll which is driven by a motor, not shown. Guide rollers, measur-
ing head, and spindles for the film rolls are all constructed so that
8-mm, 16-mm, or 35-mm films can be measured interchangeably.

The measuring head consists of the fixed lateral film guide 4 which
is adjustable for any standard width of cine* film, the ball-
bearing film-supporting roller 5, and the movable lateral film-
guide 6 which is attached to the swinging lever, with the movable
condenser plate attached to the lower end. The immovable lateral
film-guide 4 can be adjusted for different widths of film by lifting the
lateral positioning-pin 7 and moving the film-guide 4> until the proper
space separates it from the other film-guide. Then, by lowering the
tapered positioning-pin into a tapered hole, the guide 4 is firmly
locked in position. This tapered design of the locking mechanism
insures the same positioning of the fixed lateral film-guide whenever
it is adjusted to measure film of any particular width, regardless of
intervening adjustments for other widths of film.

As the film passes through the measuring head, it is curved over
the ball-bearing film-supporting roller 5. The path described by the
film in passing over this roller forces it into a partially cylindrical
contour at the point of measurement, thereby inducing lateral rigidity
and assuring that the true width of the film will be measured. This
simple method of film-guidance is one of the prime factors insuring
accuracy and reproducibility of readings with the instrument.

The zero-set button 8 (Fig. 2) is used for adjustment of the in-
strument, if necessary. Depression of this button, against the
tension of the return spring 9 shifts the movable condenser plate 10
to a definite predetermined position in relation to the fixed condenser
plate 11. When condenser plates are separated by this predeter-
mined distance, the lever and movable film-guide are in a position
corresponding to that which they would occupy if a film were of

400

S. C. CORONITI AND H. S. BALDWIN [J. S. M. P. E.

exactly the specified width, and neither wider nor narrower. When
measuring such a film, the instrument should give a zero reading,
and if there has been any slight drift from the correct setting, this
can be determined and corrected immediately. In effect, the zero-

FIGS. 1 AND 2.

set button serves the same purpose as a standard test-block for cali-
brating the instrument, but it eliminates the inconvenience of sepa-
rate guages which might be lost or damaged.

In designing the electronic film- width gauge, to eliminate errors
of the kind inherent in mechanical devices for precise measurement,
moving parts were restricted to the single pivoted member con-

Nov., 1943] INSTRUMENT FOR MEASURING FILM WIDTH 401

stituting the lever. This lever is pivoted off center, thereby creating
a constant pressure of l*/2 ounces against the edge of the film.

The only parts on the instrument subject to appreciable wear
are the two lateral film-guides in the measuring head. Although
these are made of specially hardened steel, in time they will become
grooved. However, each of these guides can be removed and re-
placed very easily, and carballoy, sapphire, or other superhard sur-
faces can be adopted.

Film is moved through the instrument by a small motor with
geared reduction. The speed of this motor is variable. The ac-
curacy of measurement is not affected appreciably by variations of
film speed throughout the range within which the gauge is designed
to operate.

In Fig. 2, any displacement of the lateral film guide 6 by the film 1
is transmitted to the movable condenser plate 10 by the insulated
lever 12. The condenser plates 10 and 11 are completely insulated
from the mechanical elements of the measuring head.

The fixed condenser plate 11 is grounded to the metal chassis 13
and is held in position by a fine-thread screw attached to it. By
rotating this condenser plate, the distance between the two con-
denser plates can be readily adjusted.

The upright member of the chassis assembly 14, in addition to
acting as a support for the horizontal member from which the lever
is suspended, acts also as a shield for the movable condenser plate 10.
Inasmuch as the instrument acts on a change in capacitance, any
foreign metallic object approaching the condenser plate introduces
additional capacitance which leads to erroneous readings. A very
fine and flexible wire connects the movable condenser plate with a
conductive metal rod 15 surrounded by an insulating tube 16 of
polystyrene resin.

Discussion of Electrical Requirements. — Small linear displacements
have been measured electronically by early investigators.1'2 The
small linear displacement to be measured was coupled mechanically
to a variable electrical condenser in an electronic circuit. There-
fore, variations of displacements were translated into changes of
plate current, measured by a sensitive galvanometer, or by changes
in the oscillation frequency of an oscillatory circuit. Practically
both these methods are restricted to laboratory usage. For routine
production operations, an instrument must be rugged and accurate.
In the circuit described in this paper, the sensitive galvanometer

402

S. C. CORONITI AND H. S. BALDWIN [J. S. M. P. E.

has been replaced by an inexpensive 0-1 milliammeter, which is
rugged and can be used by any unskilled operator.

The resonance circuit consists of an inductor L and two capacitors
C\ and Ci connected in parallel.

If A is the surface area of the two parallel plates 11 and 12 (Fig. 2)
and d is distance between them, the capacitance is given by

c = M-, u)

6K6 GT/G

/20v.

FIG. 3.

If d is decreased by a small distance Ad, the change in capacitance is
given

4ird d + Ad

(2)

From equation 2 it is seen that the sensitivity of the variable con-
denser depends upon the distance separating the two plates. By
making d very small, the change of capacitance is greater for a given
change of Ad. However, in this instrument the minimum distance
is limited by the maximum change of film width. If linearity is
desired, distance is limited also by the change of slope of equation
2. For very small values of d, the change in capacitance is greater

Nov., 1943] INSTRUMENT FOR MEASURING FILM WIDTH

403

for negative values of Ad than for equally positive values, and a
minimum distance d can be found that will yield a negligible per-
centage of error for small =*= Ad variations.

The average variation of width in 35-mm, 16-mm, and 8-mm films,
permissible within tolerances established by SMPE standards, is
0.07 mm. In the present instrument, the areas of condenser plates
and the distance between the plates are such that the change of
capacitance to be detected is extremely small.

FIG. 4.

Small variations of capacitance can be measured conveniently
by their effect upon the frequency of an oscillator circuit or by their
effect upon the amplitude of current in a parallel resonance circuit.
Fig. 3 is a diagram of the present electronic width-gauge. Essentially
it is a fixed vacuum-tube oscillator loaded by a variable parallel tuned
circuit, the impedance of which varies with the capacitance fluctua-
tion of the mechanical condenser C*. As a result, the direct current
flowing through the vacuum tube varies, and these variations are
directly proportional to variations in width of the film or other object
being measured.

404

S. C. CORONITI AND H. S. BALDWIN [J. S. M. P. E.

The capacitor C\ is a fine control to compensate for minor fluctua-
tions in frequency. If reproducible results are desired, it is ex-
tremely important that the resonance at which the circuit operates
be confined to one point on the resonance curve. Assuming that the
overall capacitance is changed by a very small amount to some value
less than that required, the change of current for a given change of
capacitance will be less because of the non-linearity of the resonance
curve. If the curve were linear, the drifting of the operating point
caused by a change of capacitance would not introduce errors into
the measurements.

200

of \JIOT H

FIG. 5.

The source of oscillation is a quartz crystal connected to the grid
of a 6K6GT/G vacuum tube. The parallel resonance circuit is
connected to the screen grid, a feature of design leadfng to increased
stability of operation. The plate and screen grid are operated at
hah7 their rated voltages. Power supply is a 6ZY5G full- wave
rectifier with a VR-150-30 connected across a fraction of the bleeder
resistance R\. The screen is fed by a shunt consisting of an r. f.
choke, a 0-1, d-c milliammeter or 0-1 d-c recording milliammeter and
a rectified source of voltage which is used to balance out the normal
current flowing in the screen.

Nov., 1943] INSTRUMENT FOR MEASURING FILM WIDTH

405

This rectifier circuit consists of two small selenium rectifiers Si,
which feed a variable resistive load. The source of power for this
circuit is the voltage across the rectifier filaments, and no additional
filtering is necessary. A half-wave rectifier was not used in this
circuit because it caused vibration of the recording stylus.

The component units of the electronic circuit were selected to
minimize the generation of heat, for it is known that the impedance
of a tuned circuit and of the tube elements are functions of the sur-
rounding temperature. Accordingly, the screen-grid current will
fluctuate if the necessary precautions are not observed to prevent
fluctuations of temperature. With the present circuit, after ap-
proximately five minutes for heating, no drift in screen-grid current

\ \

\ \ \

\ \

\ / \

V V

J V

!=t

FIG. 6.

was noticed during continuous operation for 48 hours. The stability
of the circuit is excellent.

Operation of the circuit is illustrated graphically in Fig. 4, which
shows the relation between screen-grid current and capacitance of
the resonance circuit. In a crystal oscillator circuit, the resonance
curve is not symmetrical, one side of the curve having a slope much
greater than the other. This effect is caused by the influence of the
tuned circuit upon the crystal impedance.3 When film is held
between the fingers, as in threading the width-gauge, the capacitance
is varied so the circuit is no longer in resonance, as indicated by a
or some other point on the curve. The direct current / corresponding
to point a is balanced until the meter reading corresponds to the de-
sired reading on the scale. As the width of the film becomes greater
or less than the width corresponding to a zero setting of the width-
gauge, the meter indicates a flow of current greater or less than the

406

S. C. CORONITI AND H. S. BALDWIN [J. S. M. P. E.

value represented by the point a on the curve. Once this point for
correct operation has been determined, calibration of the instrument
becomes simple. The zero position on the meter is checked occasion-
ally by pressing the zero-set button 8 (Fig. 2) .

The difference in current can be materially amplified by simply
increasing the efficiency of the resonance circuit, that is, by increasing

FIG. 7.

its Q value. The sensitivity to small changes of capacitance can be
increased also by increasing the frequency of the generator.

For linear differences of current with changes of capacitance, the
circuit should be operated on the part of the resonance curve where
the change of slope is zero. With only small changes of capacitance,
such a portion of the curve does exist for practical purposes. In the
present instrument, this portion of the curve corresponds to a linear
response for changes of capacitance effected by variations of film
width not exceeding 0.25 mm. Fig. 5 is a curve obtained by measur-

Nov., 1943] INSTRUMENT FOR MEASURING FILM WIDTH

407

ing known widths of 8-mm film and plotting the values against the
current response. The curve shows the linearity of the circuit.

By replacing the d-c meter by a recording milliammeter, such as
that made by the Esterline- Angus Company, Inc., continuous auto-
matic recording of variations in width can be achieved. The speed
of the recording chart and of the film can be adjusted to suit the con-
venience of the operator.

FIG. 8.

Fig. 6 shows a section of the record of width variation in a 50-ft
roll of 8-mm film. A shows a maximum width variation of 0.045
mm, and B shows a maximum width variation of 0.002 mm.

Fig. 7 is a photograph of the complete electronic film- width gauge,
opened to show its component parts. Fig. 8 shows the case when
closed, with a 0-1, d-c milliammeter, calibrated directly in milli-
meters.

408 S. C. CORONITI AND H. S. BALDWIN

Reproducibility of Results. — It is very necessary that a control in-
strument be reliable. It must give accurate and reproducible results
over long periods of time, with minimum variation. Table II shows a
comparison of results obtained with the electronic width-gauge and
with the Zeiss stereo comparator. In this test, three points on a
strip of 16-mm film, which had been processed and shrunk, were
selected at random. Each of these points was read five times by the
same operator, using each of the two instruments, and the readings
were recorded as follows:

TABLE n

Electronic Width-Gauge

Zeiss Comparator

Point Number

(mm)

15.866

15.855

15.864

15.868

15.854

15.861

15.868

15.854

15.866

16.866

15.854

15.867

15.866

15.856

15.867

15.869

15.856

15.868

15.866

15.857

15.866

15.870

15.855

15.865

15.867

15.855

15.865

15.868

15.855

15.865

Average

15.866

15.855

15.865

15.868

15.855

15.865

Variation

0.002

0.003

0.004

0.002

0.007

From these tables it is apparent that the electronic width-gauge
gives readings of great precision and with reproducibility superior
to instruments formerly used for determining film-width. The con-
tinuous recording of film-width also has allowed certain studies to be
made in connection with the smoothness of slitting, leading to re-
finements of manufacturing procedure and engineering control sur-
passing original expectations.

REFERENCES

1 WHIDDINGTON, R. : "The Ultra Micrometer," Phil Mag., 40, series 6, No. 256
(1940), p. 63.

2 BOWLING, J.: "Direct-Reading Ultramicrometer," Roy. Dublin Soc., 16,
(1920-1922), p. 187.

HENNY, K.: "Electron Tubes in Industry," textbook, 2nd Edition, p. 447.
* VIGOUREUX, P.: "Quartz Resonators and Oscillators," H. M. Stationary
Office (London), 1939.

CONSERVATION OF PHOTOGRAPHIC CHEMICALS
ALLAN HAINES**

Summary. — A chemical and a mechanical method of conserving photographic
chemicals in the processing laboratory are described.

The purpose of this article is to present to the black-and-white
photographic processing laboratory a means of conserving photo-
graphic chemicals without a reduction in the quality of the product.
This conservation is accomplished by a chemical method and a me-
chanical method.

CHEMICAL METHOD

The chemical method originated several years ago and is currently
in successful use by several laboratories which demonstrates its practi-
cal value. The method utilizes the excess volume of negative de-
veloping solutions, which is normally discarded, as a source of part
of the chemicals needed for the positive developing solutions. The
principal source of this excess volume is found in the negative-action
developer and the variable-density type sound-track developer. Both
of these solutions are rich sources of sodium sulfite, and, in addition,
the latter is usually a good source of metol and hydroquinone. These
three materials represent the most important items in a chemical
budget.

There are six essential materials involved in the composition of the
various developing baths commonly used in a black-and-white proc-
essing laboratory :

Negative- Action Variable- Density

Developer Sound-Track Developer Positive Developer

Metol Metol Metol

Hydroquinone Hydroquinone Hydroquinone

Sodium sulfite Sodium sulfite Sodium sulfite

Sodium metaborate Borax Sodium carbonate

Potassium bromide Potassium bromide Potassium bromide

Water Water Water

* Presented at the 1943 Spring Meeting at New York.
** Pathe Laboratories, Inc., Los Angeles.

409

410

A. HAINES

U. S. M. P. E.

In the above list the alkaline materials (i. e., sodium metaborate,
borax, and sodium carbonate) are the only ones not common to the
three formulas.

The above alkalies vary in strength depending upon the concen-
tration of hydroxyl ions which each supplies to the solution. If the
alkali is strong, as sodium carbonate, it furnishes a high concentration
of hydroxyl ions and the pH of the solution is said to be high. If the
alkali is weak, as borax, both the hydroxyl ion concentration and the
pH of the solution are relatively low.

LIQUID LEVEL

MACHINE TANK-

LEVER

FLOAT

BUTTERFLY
VALVE

MACHINE TANK

FIG. 1.

PUMP

A typical circulating system with butterfly valve control in the
return pipe line.

The developing agents metol and hydroquinone depend upon the
pH of the solution in which they are dissolved for the rate at which
they form a silver image in a photographic emulsion. It is known that
the pH value of a developing solution is one of the most important
factors in determining the character of that solution. In general,
negative solutions have a low pH value and positive solutions have a
high />H value. Therefore, if one raises the pH of a negative-developer
solution by the addition of a strong alkali, that solution takes on the
characteristic of a positive developer.

The successful utilization of excess developing solution depends
upon the application of a systematic chemical analysis in order to show
the additions necessary to convert the negative solution to a positive-
developing solution. Usually the metol, hydroquinone, or sodium

Nov., 1943] CONSERVATION OF PHOTOGRAPHIC CHEMICALS 411

sulfite will be present in higher concentration in a negative solution
than is desired in a positive-developing bath. Therefore, the solution
must be diluted with water until the material in highest concentration
in the negative solution is at the proper value for the positive de-
veloper. From this known dilution can be calculated the additional
amounts of the other materials which must be added to give the
correct composition.

The next step is to adjust the pH. of the solution. Sodium carbonate
plus a small amount of sodium hydroxide is used since sodium car-
bonate alone is not strong enough to give the proper alkalinity to the
solution. The amounts of these two alkaline materials which must
be used depend upon the activity desired in the positive developer.
To insure the proper addition, measurements are made on the solu-
tion with a pH meter. The speed of the developing machine de-
pends, to a considerable extent, upon the activity of the developer,
and, therefore, the amount of alkaline addition must be worked out
to fit the requirements of each individual laboratory.

MECHANICAL METHOD

The mechanical method of conserving photographic chemicals
reduces the aeration of the developer while it is being circulated in
the developing-machine tanks and reduces the amount of foam forma-
tion. Up to ten per cent of the metol, hydroquinone, and sodium
sulfite can be lost by aeration by the oxygen in the air. The elimina-
tion of foam removes a nuisance and also the necessity for breaking
down the foam at intervals with octyl alcohol or a similar reagent.

Aeration of the developer is prevented by adding a float-controlled
butterfly valve to the return line of the circulating system in order to
maintain a fixed level in the tank. The valve and float automatically
meter the amount of fluid flowing out of the tank. Once the length
of the lever arm to the float is adjusted, the return flow will remain
fixed as long as the circulating pump of the system maintains a rea-
sonably constant output.

Fig. 1 shows a typical circulating system with the butterfly valve
control in the return pipe line. The exact arrangement of course will
vary with different types of machines. In this particular system 2-
inch valves have been found adequate to circulate about 75 gallons
per minute of liquid from a machine tank which is about 8 feet above
the liquid level in the circulating tank. The relative heights of the ma-
chine tank and the circulating tank, as well as the capacity of the cir-
culating pump, must be considered in selecting the proper size of valve.

MAPS ON MICROFILM
SOME FACTORS AFFECTING RESOLUTION*

MICHAEL BRUNO**

Summary. — Results of research on the reproduction of maps in 35-mm color and
black-and-white film are described. This research involved a thorough study of the ef-
fect of material, equipment, and processing on resolution. Observations of these ef-
fects have been carefully studied and the results are presented with a discussion of some
of the factors influencing them.

The conclusions drawn from this research are: (1) The reproduction of colored
maps in color on 35-mm film is impossible because of the low resolving power of present
color emulsions. (2) Reproduction of colored maps in monochrome on 35-mm is not
satisfactory because of grain clumping in magnification above 20x. (5) The resolu-
tion of an image is a composite function depending on the degree of correction in the
optical system producing it, the resolving power of the material reproducing it, and the
processing it undergoes.

EXPLANATORY

The research which produced the observations and conclusions de-
scribed in this paper originated from the desire to reproduce maps in
color on microfilm which, on projection onto a translucent screen,
would provide a satisfactory substitute for the original map. The
success of such a project would offer many obvious advantages —
microfilm would conserve space, and reproduction in color would in-
sure accuracy of interpretation.

Maps are complex line patterns in color where each color depicts
definite specific information, the loss of any of which would seriously
impair their usability and reliability. The order of fineness of detail
often extends to six-point, lower-case type, or approximately four
lines per millimeter, and in many cases of finely contoured maps it
might even approach ten lines per millimeter. The use of color on
maps reduces visual contrast, and it is not unusual on some maps to
have line patterns or detail in color so fine that they can not be ade-
quately interpreted without the aid of a magnifier. Also, some maps

* Presented at the 1943 Spring Meeting at New York.
** Captain, U. S. Army Map Service, Washington.
412

MAPS ON MICROFILM

413

are so large as to require a 30# reduction for inclusion on a double
35-mm non-perforate frame.

Hence, the satisfactory production of reduced photographic rec-
ords of maps involves the consideration and study of two problems;
namely, color reproduction and resolution. It was anticipated that
some difficulties would be encountered in this project, because

1.0

2.0

FIG. 1. Resolution target chart.

critical examination of results of test exposures made on three differ-
ent types of microfilming equipment indicated that these systems did
not produce sufficient resolution even for the reproduction of the
original maps in monochrome.

Standard microfilming practice has been designed for the photog-
raphy of originals possessing high visual contrast, but the reproduc-
tion of colored maps in monochrome produces areas of low contrast in
the negative where resolution is affected by a number of factors.
Consequently, it was planned to investigate microfilming practice and

414 M. BRUNO tf. s. M. P. E.

methods thoroughly and endeavor to develop a high-resolution system
which would produce a maximum resolution on standard available
color media, and in this way determine conclusively the limit of reduc-
tion which maps would allow.

EQUIPMENT

To accomplish this and isolate and study the effects of most vari-
ables on resolution, a precision photographic system was installed on
an optical bench. The system was so designed that lenses could be
interchanged, and a movable focus plane was so adjusted that it
coincided absolutely with the emulsion plane. This system was used
for some time, but in later experiments it was superseded by a
specially fitted precision process camera in which the focus plane, lens,
and copyboard are mounted on a sturdy, shockproof frame.

The map to be photographed for resolution tests is fitted with
resolution charts (Fig. 1) in the center and at the four edges. These
target charts1 consist of ten radial and tangential line patterns, com-
posed of five lines and intervening spaces of equal width, and vary-
ing in fineness from one to 10 lines per millimeter. A removable,
chemically grained glass plate with a transparent center serves as a
focusing screen.

Images are focused with a Lomara portable microscope that has
been prefocused on the front surface of the glass. Exposures are made
on cut film that is held in the focus plane by a glass plate coated
evenly with Stay-Flat solution. This method of supporting the film
seemed questionable at first, but numerous checks and reproducibility
of results indicate that it is extremely accurate and reliable. Since
resolution was the only consideration in this photography, it was
decided to use a graphic film of the slow, fine-grain, high-contrast,
high-resolution type.

OBSERVATIONS

With this equipment and material, the effect on resolution of de-
velopers, exposure, processing, and lenses was observed. These ob-
servations have been carefully studied and analyzed, and their results
are presented with a discussion of some of the factors influencing them.

Developers. — The effect of developers on resolution was one of the
first observations made in this research and the results were very re-
vealing. Since graphic film was used, it was processed in the recom-
mended developer, which is D-85, a hydroquinone-paraformaldehyde

Nov.. 1943]

MAPS ON MICROFILM

415

developer. Examination of the resolution targets showed effects very
similar to those produced by an image out of focus (Fig. 2). The
highest average resolution attainable with this developer at recom-
mended time and temperature was 24 lines per millimeter, while the
rated resolving power of the material is approximately 100 lines per
millimeter. No amount of correction in focus could improve these re-
sults.

Consequently, it was suspected that the developer was either caus-
ing or contributing to this effect. A change to D-72 diluted 1:2
with water confirmed this suspicion. At the focal plane established
by the use of the Lomara microscope, it was possible to produce with

FIG. 2. 25* photomicrograph of nega-
tive developed in D-85.

this developer on one specific type of graphic film a resolution of 100
lines per millimeter. However, the use of D-72 produces a trouble-
some fog density, characteristic of most metol developers, which re-
duces contrast and interferes seriously with readability. It was pos-
sible to eliminate this fog density and retain the resolution by the use
of a standard but not commonly known developer, GD-190 (Fig. 3),
the chief ingredients of which are hydroquinone, carbonate, and
citric acid.2 Several so-called "fine-grain" developers were tried in
this research, but none could improve the resolution obtained with
GD-190 and D-72.

This observation is theoretically interesting because it seems to re-
fute the statement of Ross and other writers who claim that the com-
position of a developer has no effect on the resolving power of an

416 M. BRUNO tf. s. M. P. E.

emulsion.3 While this statement was substantiated by the fair con-
sistency in resolution attainable with a number of different types of
developers, a definite and serious degradation of resolution was ob-
served with the use of D-85 and other hydroquinone-paraformalde-
hyde developers. The only explanation for this phenomenon is that
these developers produce such high contrast that they are sensitive
only to a narrow range of exposures or subject brightnesses. In the
small resolution targets, or in fine detail where the lines are narrow
and very close together, there is not enough difference in subject
brightness between the lines or patterns to be included in the narrow

FIG. 3. 25x photomicrograph of nega-
tive developed in GD-190.

range on which the developer acts, so that the result is a blurred
image possessing poor resolution.

This observation has led to important conclusions in process
photography for photomechanical reproduction where high contrast is
necessary and preservation of fine detail is desirable. As stated
previously, hydroquinone-paraformaldehyde developers, as custom-
arily recommended and used on graphic films, are sensitive only to
narrow ranges of subject brightness so that they can reproduce copy
containing either all coarse patterns or all moderately fine patterns,
but can not satisfactorily reproduce copy containing both without
emphasizing one at the expense of the other. On the other hand,
GD-190 produces adequate contrast for photomechanical purposes,
and it possesses a sufficiently long scale to allow it to reproduce satis-
factorily both coarse and fine patterns simultaneously. GD-190 offers

Nov., 1943] MAPS ON MICROFILM 417

another advantage in that it possesses a longer useful life and is more
consistent in action than developers of the hydroquinone-para-
formaldehyde type.

Exposure. — The effect of exposure on resolution has been studied
and results indicate that slight improvement in resolution can be
gained from overexposure and underdevelopment. It is believed that
underdevelopment produces a surface image by not allowing the de-
veloper to act on the silver grains in the lower layers of the emulsion;
and overexposure activates sufficient grains in the emulsion to pro-
duce the desired density and contrast in the surface image. Under-
development also has the effect of reducing the graininess of the image4
resulting in better resolution.

FIG. 4. 20x photomicrograph. FIG. 5. 30x photomicrograph.

Processing. — The processing of photographic emulsions produces an
effect on resolution as a result of its influence on granularity. By
processing is meant the handling of the photographic material after
exposure, through the development, fixing, washing, and drying
stages. The literature is replete with references and recommenda-
tions for fine-grain processing, but in this investigation it was ob-
served that even under the most ideal processing conditions, negatives
were obtained in which granularity was resolvable at 20x magnifica-
tion and at 30x was so apparent that it seriously interfered with the
line patterns (Figs. 4 and 5).

This phenomenon is the limiting factor in the monochromatic
reproduction of colored maps. It is caused primarily by the fact that
gelatino-silver halide emulsions are composed of discrete, crystalline

418 M. BRUNO tf. s. M. P. E.

grains of silver halides of varying sizes dispersed in a hydrophilic
medium, gelatin. In the development process the gelatin swells,
allowing diffusion of the developer, and the silver halide grains ac-
tivated by exposure to light are reduced to corresponding grains of
metallic silver. The gelatin remains in a swollen condition through-
out the processing until dried, and any factors which accelerate or re-
tard the rate of swelling of the gelatin promote the agglomeration of
the silver grains into unsymmetrical groups, or clumps, producing
granularity.5

The more important factors which affect the rate of swelling of
gelatin include temperature, time, />H, and composition of electro-
lytes,6 and unless these are controlled the effect of granularity becomes
serious. This effect is believed to be the result of reticulation because,
theoretically, in negatives developed to the same density and gamma
the conditions under which processing is conducted should have no
effect on granularity.7

It is known that the effect of grain clumping is most apparent in
areas of low and medium density.8 In areas of high density, where the
silver halide grains are completely activated by light, grain clumping
disappears; or rather, it progresses to the degree that the clumps
overlap, leaving no clear spaces between them. High contrast origi-
nals can, therefore, be reproduced with a minimum of granularity, and
it is this fact which is responsible for most of the success enjoyed by
standard microfilming practice.

Lenses. — The effect of lenses on resolution was studied exhaustively
because it is unquestionably the most important direct factor in-
fluencing resolution. Many lenses were investigated in this research
and several important observations resulted which are not specifically
described or adequately explained in the literature. Among the
lenses tested were a 50-mm Eastman Ektar, a 63-mm Goerz Dagor,
a 4-inch Goerz Apochromat Artar, a special 195-mm Eastman Ektar
//4.5, a 24-cm ZeissApotessar, a 12-inch and a 19-inch Goerz Apochro-
mat Artar. All of these lenses are of the well-corrected process design
and they were specially selected so that as a whole they represent
approximately the highest degree of precision attainable in this
range of focal lengths.

The 50-mm Ektar was a fixed aperture lens and under ideal process-
ing conditions it produced negatives on microfilm with a resolution of
120 lines per millimeter on the axis and 95 lines per millimeter at 15°
off the axis. All the other lenses possessed variable apertures, and

Nov., 1943] MAPS ON MICROFILM 419

exposures at full aperture showed higher resolution on the axis than
at 15°. Also, the axial resolution for all the focal lengths up to and
including the 24-cm Apotessar was approximately the same, but that
of the 12-inch and 19-inch Artars was progressively lower. Decreasing
the aperture in the focal lengths through the 24-cm Apotessar caused
a slight loss in resolution on the axis and an appreciable increase at the
edges of the field. In stopping down the 12-inch and 19-inch Artars,
the overall resolution was improved, the edges improving at a faster
rate than the center up to a specific aperture, after which the axial
resolution suffered a loss which increased as aperture decreased.

These observations indicate, for well-corrected lenses of similar
design, the existence of two types of lens behavior depending on focal
length. An explanation of this requires the consideration of the
factors influencing the formation of an image. This is best done by
dividing the image into axial and outer zones and considering the ef-
fect of optical phenomena in each zone.

Assuming good color correction, the resolution of the image on the
axis is determined by spherical aberration and diffraction. Generally,
in long-focus lenses of moderate apertures, resolution on the axis is
limited by spherical aberration, while in short-focus lenses it is limited
by diffraction. In the range of focal lengths where the resolution is
controlled by diffraction, a change in focal length does not change
the resolution, but in the range where it is controlled by spherical
aberration, an increase in focal length causes a decrease in resolution.

If the resolution of a lens is limited by spherical aberration, as in
the case of the 12-inch and 19-inch Artars, it can generally be im-
proved by decreasing the aperture, eliminating the marginal rays that
cause the effect of spherical aberration. There is a limit to this stop-
ping down, because when the aperture approaches a size where it is
affected by diffraction a loss in resolution will result. In any case, the
best resolution attained is less than that of a corresponding lens of
shorter focus for which the resolution at full aperture is limited by
diffraction. In these lenses, decreasing the aperture increases the
diffraction, resulting in a loss in resolution. A comparison of these
facts with results observed in this research indicates that the lenses
up to and including the 24-cm Zeiss Apotessar can be considered in the
class of short focal lengths affected by diffraction, while the 12-inch
and 19-inch Goerz Artars are long-focus lenses limited by spherical
aberration.
... The consideration of the outer zones of the lens offers several com-

420 M. BRUNO [J. s. M. P. E.

plications. As a general rule the resolution in the outer zones of a lens
is poorer than it is in the center. This is caused chiefly by curvature of
field. This aberration indicates that when a flat surface perpendicu-
lar to the axis of the lens is photographed, the image is not a flat
surface but is a surface of revolution with a bulge away from the plane
of focus (Fig. 6). The amount of bulge or departure from emulsion
plane is directly proportional to the focal length in specific lens de-
signs. The presence of this bulge in the focal surface prevents coinci-
dence of the focal surface and emulsion planes in the off-axis areas of
the image, resulting in damage to definition or resolution of the image
in these zones. Decreasing the aperture increases the depth of focus

FIG. 6. Curvature of field.

of the lens, effecting an improvement in resolution in the outer zones.
There is a limit to this improvement caused by the complex effect of
diffraction on the image points in this zone when apertures get
too small.

From this discussion, the selection of an optimum working aperture
to produce maximum overall resolution is a critical matter. Aperture
must be decreased to improve the resolution of the outer zones, and
in short-focus lenses it is decreased to the point where the outer
zones produce sufficient resolution without seriously impairing that
of the center. In longer focal lengths both zones improve in stopping
down until the aperture approaches the size where diffraction reduces
the resolution on the axis. In process-type lenses of moderate aper-
ture, this is usually between two and three stops from the maximum

Nov., 1943] MAPS ON MICROFILM 421

aperture. In the 24-cm Zeiss Apotessar //9, the optimum aperture
is//16, and in the 19-inch Goerz Artarf/ll, it is//22.

In the course of this investigation of lenses another interesting
observation was recorded. It was observed that with the 24-cm
Zeiss Apotessar it was possible to produce an image on graphic film
possessing a resolution of 100 lines per millimeter on the axis and 79
lines per millimeter at 15° off the axis. Photography through this
same system onto a color medium of necessarily lower resolving power
produced an image possessing a resolution of 40 lines per millimeter on
the axis and only 32 Hnes per millimeter at 15°. While it might be
expected that an optical system capable of producing at least 79
lines per millimeter over the whole field should produce maximum
resolution all over a medium of lower resolving power, actually there
is a loss in resolution between axial and outer zones on the low re-
solving power emulsion similar to the drop in resolution for the two
zones on the high resolving material. Resolution, therefore, is not an
absolute optical quantity, but is a measure of the relative degree of
correction in a lens, and the analysis of resolving power data on lenses
should take this factor into account.

Optical Printing. — Since the final image is to be viewed and read
from a screen, negatives are not desirable, so they must be converted
to positives. In the production of these positives several important
observations were made. Positives have been made on three differ-
ent continuous 35-mm printers, using several fine-grain microcopying
positive emulsions, and in no case has the resolution of the positive
been greater than two- thirds that of the negative. On the other hand,
duplicate negatives made on Ozaphane in a standard Ozaphane
printer show a loss in resolution of less than 10 per cent.

These observations have not as yet been fully analyzed, so no
attempt is made to explain them. In fact, this part of the research is
still active because considerable monochromatic microfilming of
colored maps is being done for purely identification and indexing
purposes. While the negatives possess sufficient resolution for these
purposes, the loss of 35 to 40 per cent of this resolution in the viewing
positives is a serious handicap.

Viewing Systems. — Some brief observations have been made of the
effect on the resolution of the final image of different types of viewing
systems. Projected images onto specific reflecting screens possess
higher resolution than images projected onto translucent screens.
The failure of translucent screens is occasioned by the fact that they

422 M. BRUNO tf. S. M. P. E.

incorporate a diffusing medium to eliminate a hot spot in viewing.
Since the projected light is the image, diffusion of the light is equiva-
lent to diffusion of the image, or loss of resolution. Reflection view-
ing of projected images of maps is not desirable, so translucent
viewing, such as is incorporated in the conventional microfilm reader,
is used in spite of the loss of resolution which it introduces.

In connection with projection, it has been observed that the pres-
ence of granularity or grain clumping in the negative or positive has a
serious effect on resolution at magnifications above which it can be re-
solved. At magnifications above 20x the intervening spaces between
the grains act as a diffusing medium for the light, causing diffusion of
the image and damaging its resolution.

Another method of viewing has been investigated in the course of
this research. This is direct magnifying viewing in which the nega-
tive or positive is viewed directly with the aid of a wide-angle magni-
fier. This system causes the least effect on resolution because the
image is viewed directly and is not required to travel through an elab-
orate optical system as in projection, but it offers the disadvantage
of fixed magnifications. Also, suitable wide-angle magnifiers in the de-
sired magnification range are not readily available. Such viewers
would be suitable as a portable means of examining microfilm.

Color. — The reproduction of maps on color-film presents other
serious difficulties. The first of these is color balance. Multilayer
color-films consist of three emulsions of specific spectral sensitivities,
and the color composition of the light must be adjusted so that it
coincides with these sensitivities, otherwise true color rendition is not
possible. Color composition is controlled by the light-source and
filters, and their effect on resolution has been observed and studied.

Color temperature is a measure of color composition and correction
filters are available which convert the color temperature of a specific
light-source to a light of standard color temperature. Multilayer
color-films are designed for good color balance with light of one of two
standard color temperatures— 5400° K, or daylight, and 3200°K, or
Mazda. Any variations in the color temperature of the light-source
will produce corresponding variations in the color temperature of the
filtered light, so that for proper color rendition all the factors affecting
variation of color temperature must be controlled.

Color rendition, of course, has no relation to resolution, but the use
of correction filters has. In the course of this research it was observed
that any obstacle introduced in the optical train of the photographic

Nov., 1943] MAPS ON MICROFILM 423

system impairs the resolution of the image. Many types of correction
filters were used — before, behind, and between the lens — and all pro-
duced this effect to a greater or lesser degree. Some filters showed as
many as five fringes around each line, and even so-called "optically
inert" gelatin filters produced a loss in resolution greater than 10 per
cent. Correction of color temperature is best accomplished by using
the filters over the light-source. While this method requires much
larger filters, inexpensive types can be used because optical activity
in the filters has no effect on the characteristics of the optical system.
The other difficulty encountered in the use of color-film is the low
resolving power of emulsion. In monochromatic photography good

FIG. 7. 25x photomicrograph of Ansco
color transparency.

resolution of image is possible because emulsions can be selected
which possess resolving power greater than that of the optical system,
but in multilayer color emulsions the resolution of the final image suf-
fers, not only from the aberrations of the optical system but also from
the low resolving power of the emulsions themselves.

Both Kodachrome and Ansco Color were investigated in this re-
search, and it was found that the resolution of both standard materials
under similar optical conditions was in the neighborhood of 40 lines
per millimeter on the axis (Fig. 7). In view of this and of the fact
that Ansco Color could be readily processed by the user, the majority
of the investigations in color was conducted on this medium.

Ansco Color film is a monopack, or multilayer color process,
possessing three balanced gelatino-silver-halide emulsions, each layer

424 M. BRUNO [j. s. M. P. E.

of which is sensitized to record one of the tricolor components of the
spectrum.9 The emulsion layer next to the support is red-sensitive,
the middle layer is orthochromatic green-sensitive, and the top emul-
sion layer is color blind blue-sensitive. Each layer contains non-
diffusing dye-couplers which in processing combine with the color
developer to form transparent colors complementary to the color for
which each emulsion layer is sensitized. Kodachrome is similar to
this, except that no dye-couplers are used in the material. The in-
dividual emulsion layers are selectively dyed during processing by ex-
posure to colored lights and development in dye-coupling developers.

The manufacture of such products is an extremely difficult process
requiring delicate control and a high degree of precision. For all
emulsion layers to expose together and for proper color rendition, the
individual emulsions must be critically balanced for speed, contrast,
and color sensitivity corresponding to a standard color temperature
of either 3200°K or 5400°K.

In order to produce a final product of moderate speed, the constitu-
ent emulsions must be relatively fast. Fast emulsions are generally of
low resolving power because of their grain structure. It is evident
then that the superposition of three such emulsions must necessarily
produce a medium of low resolution. Since no variations in exposure
and processing are permissible, little can be done to correct this condi-
tion in standard commercial color emulsions where moderate speed
and long-scale reproduction are desired. In map reproduction, how-
ever, slower speeds and higher contrast or shorter scale are desirable.
Both Eastman Kodak and Agfa Ansco have produced experimental
multilayer films specifically for this problem, consisting of slower, fine-
grained individual emulsion layers, and while color rendition suffered
somewhat from unbalanced contrast in the layers, resolving power was
improved to produce an image with 56 lines per millimeter on the axis.
Little hope is held out for further improvement of this resolution
soon, because of the pressure of other important problems, and be-
cause of the difficulty of changing and balancing the emulsions com-
posing a multilayer color-film.

CONCLUSIONS

As a result of the observations made during this research and a
careful study and analysis of their results, several important conclu-
sions can be drawn :

(1) The reproduction of colored maps in color on a double non-

Nov., 1943 J MAPS ON MICROFILM 425

perforate 35-mm frame is impossible, because multilayer color-film
materials do not possess the necessary resolving power. Reductions
of 10# are possible using critical focusing and a high-resolution
optical system similar to the 24-cm Zeiss Apotessar.

(2) The reproduction of colored maps in monochrome on a double
non-perforate 35-mm frame is not satisfactory, because at minifica-
tions above 20# the phenomenon of grain clumping seriously inter-
feres with fine line patterns, especially in areas possessing intermediate
tones. It is, therefore, recommended that for continuous tone sub-
jects the reductions be limited to I5x and for large subjects 70-mm
roll film should be considered.

(3) The resolution of an image is a composite function depending
on the degree of correction in the optical system producing it, the re-
solving power of the material reproducing it, and the processing
which it undergoes. All factors that affect any of these processes will
affect the resolution of the final image.

REFERENCES

1 These targets were originally designed by the Photographic Section of the
National Bureau of Standards, and a modification of this design is distributed by
Agfa Ansco, Binghamton, New York.

2 "Materials and Technique for Photomechanical Processes," The Gevaert Co.
of America, Inc. (1939).

FORMULA GD-190

Hydrochinon (High Contrast — Long Life)

Water (about 125°F, 52°C) 2000 cc.

Potassium Metabisulfite 30 g.

Sodium Sulfite (anhydrous) 120 g.

Hydrochinon 90 g.

Sodium Carbonate (monohydrated) 240 g.

Citric Acid (crystals) 5 g.

Potassium Bromide 12 g.

Water to make 4000 cc.
Time of development: 4 to 5 minutes at 65° to 70°F (18° to
20°C).

3 MEES, C. E. KENNETH: "The Theory of the Photographic Process," p. 901.

4 NEBLETTE, C. B.: "Photography, Its Principles and Practice," Fourth Edi-
tion, p. 380.

MEES, C. E. KENNETH: "The Theory of the Photographic Process," p. 85.
MEES, C. E. KENNETH: "The Theory of the Photographic Process," p. 79.
MEES, C. E. KENNETH: "The Theory of the Photographic Process," p. 865.
MEES, C. E. KENNETH: "The Theory of the Photographic Process," p. 843.
FORREST, J. L., AND WING, F. M.: "The New Agfacolor Process," /. Soc.
Mot. Pict. Eng., XXIX, 254 (1937).

SENSIBLE USE OF REFRIGERANTS UNDER THE EMER-
GENCY NOW CONFRONTING THE INDUSTRY

A. C. BUENSOD AND R. W. WATERFILL*

Summary. — Under Conservation Order M-28, which was amended as of Sep-
tember 7, 1943, the use of additional Freon (F-12) has been prohibited in comfort
cooling installations and its use greatly curtailed in all but essential food and essen-
tial industrial processes. This had led to the obvious conclusion that a less critical
substitute be used, which, for practical reasons, means methyl chloride.

This article emphasizes the best experience of the industry to date in the hazards
involved when methyl chloride is used as the refrigerant.

The urge for substitution of Freon-12 will become increasingly greater because the
prospects for a sufficient production of F-12 is not in sight for the next cooling season,
according to the best authorities on the subject. The authors hope that the publicity
relative to the hazards involved when methyl chloride is used will be useful and that the
precautions and limitations, as outlined in the ASA safety code for refrigeration,
as well as any municipal code or ordinance, are followed.

Refrigeration and air conditioning made rapid progress in the
fifteen years preceding the outbreak of the present war. This
progress was facilitated by many things, including public apprecia-
tion and industrial necessity, as well as research, new refrigerants
standardization, and the adoption and adherence to codes and
ethical standards by the better organizations within the industry.
While it is impossible to avoid mistakes and disappointments, the
industry generally realizes its responsibility to the public.

The general public is in no position to qualify as experts on every
commodity and service it enjoys in modern life. To maintain the
high standard of American living it is therefore essential that the
public have confidence in the established producers of these com-
modities. The refrigeration and air conditioning industry has
realized this since it started producing commodities and services
directly affecting the public, and has evolved codes and standards
to protect the public and insure its merit of such confidence. This
responsibility also extends to the formulation of codes to inform and
guide civil authorities, builders, owners, etc.

* Buensod-Stacey, Inc., New York.
426

SENSIBLE USE OF REFRIGERANTS 427

The evolution of codes has been a long and difficult procedure
and one that promises to continue for some time. The reasons
for this are chiefly that the code must follow the development of
the art itself and the many uses served.

One of the principal codes of the refrigeration industry is a Safety
Code designed to protect, as far as possible, public health and prop-
erty. While the benefits of refrigeration and air conditioning are
varied and enormous — their value today is only partially realized
— it is felt that this is no excuse for compromising with safety.

Appreciating its stake in a safe and sane development of the
refrigerating industry, the American Society of Refrigerating Engi-
neers sponsored a model Safety Code for Mechanical Refrigeration
under the rules and regulations of the American Standards Associa-
tion, with the hope that it would serve as an American standard.
In order to insure fulfillment of the broad purposes of the Code
many groups, including those especially concerned with the public
interest such as Underwriters' Laboratories, Inc., National Safety
Council, etc., participated. The current Code approved by the ASA
in 1939 represents many years' work by experts in each phase of the
problem, and thus stands as a certified model for incorporation in
local regulating ordinances.

While it is admitted that no code will ever be perfect, the 1939
ASA Code is somewhat rigid in its public safeguards, and the Code
is abreast of the current state of the refrigeration art in all basic
essentials. This is particularly true in its classification of refrigerants
into groups according to the relative safety with which they may be
employed. While new refrigerants may be added to these groups as
developed and classified it is to be hoped that the safety standards
already achieved will be maintained.

The ASA group classifications based on extensive tests of toxicity
and flammability are as follows:

5.11 GROUP 1

Chemical Formula

Carbon dioxide CO8

Dichlorodifluoromethane (Freon-12) CC12F2

Dichloromonofluoromethane (Freon-21) CHC12F

Dichlorotetrafluoroethane (Freon-114) C2C12F4

Dichloromethane (Carrene No. 1) (Methylene chloride) CH2C12

Trichloromonofluoromethane (Freon-11) (Carrene No. 2) CC13F

428 A. C. BUENSOD AND R. W. WATERFILL [J. S. M. P. E.

5.12 GROUP 2

Chemical Formula

Ammonia NH3

Dichloroethylene C^Cla

Ethyl chloride CzHsCl

Methyl chloride CH8C1

Methyl formate HCOOCH,

Sulfur dioxide SO2

5.13 GROUP 3

Chemical Formula

Butane C^io

Ethane C2H6

Isobutane (CH3)3CH

Propane CsH8

The present curtailment in the use of chlorinated fluorinated hydro-
carbon refrigerants, as dictated under war activities and as shown in
the Conservation Order, M-28 of the War Production Board, brings to
the forefront the question of substitution of refrigerants where
possible in order to alleviate the serious shortage, particularly of
Freon-12.

It has. already been demonstrated that through ignorance and
through the pressure brought to bear by owners who have no con-
ception of the hazards involved in substitutions some deaths have
been attributed to the substitution of other refrigerants than the
Freon-12 for which systems have been designed. With this in mind
it is well to enumerate some of the fundamental differences in safety
precautions to be observed in connection with different refrigerants.
The full code should be studied carefully, however, to obtain com-
plete details and qualifications, but the following extracts from the
ASA Code illustrate the principal regulations :

Sec. 7 — Public Assembly Occupancies

7.20 The maximum quantity of a Group 1 refrigerant in a Direct System used
for air conditioning for human comfort shall be limited by the volume of the space
to be air conditioned as shown in the table at the top of the next column. (F-12,
30 Ibs per 1000 cf .)

(a) When the refrigerant containing parts of a system are located in one or
more enclosed spaces, the cubical contents of the smallest enclosed space other
than the machinery room shall be used to determine the permissible quantity of
refrigerant in the system.

(b) When the evaporator is located in a duct system, the cubical content
of the smallest enclosed space served by the duct system shall be used to deter-
mine the permissible quantity of refrigerant in the system unless the airflow to

Nov., 1943] SENSIBLE USE OF REFRIGERANTS 429

any enclosed space served by the duct system can not be reduced below J/4 of its
maximum, in which case the cubical contents of the entire space served by the
duct system shall be used to determine the permissible quantity of refrigerant
in the system.

7.22 A system containing more than one thousand (1000) pounds of a Group 1
refrigerant shall be of the Indirect type with all the refrigerant containing parts,
excepting parts mounted outside the building, installed in a machinery room
used for no other purpose and in which for Group 1 refrigerants, excepting car-
bon dioxide, no flame is present or apparatus to produce a flame is installed.

7.31 Group 2 refrigerants shall not be used in a system for air conditioning for
human comfort, except in an indirect Vented Closed Surface System, or in a Double
Indirect Vented Open Spray System, or in an Indirect Absorptive Brine System.

Sec. 9 — Commercial Occupancies

9.12 Refrigerant piping shall not be carried through floors except as follows :

(c) In systems containing Group 1 refrigerants and used for air conditioning
for human comfort, the refrigerant piping may be carried through floors provided
it is enclosed in an approved, rigid and tight continuous fire-resisting flue or shaft
where it passes through any intermediate space not served by the air conditioning
system. The flue shall be vented to the outside or to a space served by the air
conditioning system. Such systems shall conform to the requirements of para-
graph 9.20.

9.20 Direct Systems containing more than twenty (20) pounds of a Group 1
refrigerant when used for air conditioning for human comfort, shall be limited by
the volume of the space to be air conditioned as follows : F-12, 30 Ibs per 1000 cf .

9.22 A system containing more than one thousand (1000) pounds of a Group 1
refrigerant shall be of the Indirect type with all the refrigerant containing parts,
excepting parts mounted outside the building, installed in a machinery room used
for no other purpose and in which for Group 1 refrigerants, excepting carbon di-
oxide, no flame is present or apparatus to produce a flame is installed.

9.30 A system containing more than twenty (20} pounds of a Group 2 refrigerant
shall not be used for air conditioning for human comfort unless it is of the Indirect
Vented Closed Surface, Double Indirect Vented Open Spray, Indirect Absorptive
Brine, or primary circuit of a Double Refrigerant type with all the refrigerant
containing parts, excepting parts mounted outside the building, installed in a
machinery room used for no other purpose.

9.31 More than six hundred (600) pounds of a Group 2 refrigerant shall have
all refrigerant containing parts installed in a Class T machinery room.

Sec. 10 — Industrial Occupancies

10.10 There shall be no restriction on the quantity or kind of refrigerant used
in an Industrial occupancy, except as specified in paragraph 10.20.

10.20 When the number of employees above the first floor exceeds one per one
hundred (100) square feet of floor area, the requirements of Commercial occupan-
cies shall apply unless that portion of the building containing more than one em-
ployee per one hundred (100) square feet of floor area above the first floor, to-
gether with its entrances and exits, be cut off from the rest of the building by
vaportight construction with self-closing, tight-fitting doors.

430 A. C. BUENSOD AND R. W. WATERFILL [J. S. M. P. E.

The authors, both of whom were engaged in the pioneering days
in the use of the new refrigerants and on many occasions sat in with
municipal authorities in New York City for the purpose of assisting
in the formulation of municipal codes that are practical and which
safeguard life and property, thought it would be of interest to quote
the present provisions governing the installation of air conditioning
and refrigerating systems in the City of New York. Some of the
provisions from the prevailing Municipal Code are as follows:

C19-98.0 — Permissible Locations

(b) The direct method of refrigeration shall not be used in any building, whether
or not a permit is required for installation therein, outside of a refrigerating ma-
chinery room except in buildings used exclusively for ice making or for refrigerating
purposes, or when such method is not carried above the first floor in business build-
ings, or in the business sections of business buildings provided the entire system is
confined to one floor in the space occupied by a single tenant, or, in the business sec-
tion of a residence building when not carried above the first floor, or in a residence
building occupied by not more than two families, or in any building provided a
non-irritant and non-inflammable refrigerant is used.

(/) It shall be unlawful to install or maintain a refrigerating system employing
an irritant or inflammable refrigerant in or on: (2} Dance halls, court rooms,
police stations, jails, subways, theaters, or motion picture theaters.

(h) The use of methyl or ethyl chloride, sulfur dioxide, or a hydrocarbon re-
frigerant will not be permitted in Class A systems.

Cl 9-96.0— Permits

(c) It shall be unlawful to maintain or operate any refrigerating system em-
ploying a refrigerant other than those specified in this article without a permit
issued upon such conditions, consistent with the provisions of this article, as are
deemed by the fire commissioner necessary in the interest of public safety.

Note: The Fire Chief and Commissioner prescribed under date of April 4,
1934, the following:

(1} That the refrigerants. . .F-12. . .F-114. . .and. . .F-ll are non-flammable
and non-irritant, unless otherwise hereinafter provided, and shall be regulated in
accordance with the provisions of Article 18 of Chapter 19 of the Administrative
Code, as such, except, when used in a room or rooms in which there is an open
flame or apparatus to produce an open flame, when the provisions of said article
covering irritant refrigerants shall apply.

(2} That refrigerating systems employing F-ll, F-12, or F-114 are restricted
to parts of a building so specified in Section C19-98.0 (6) for refrigerants other than
non-irritant and non-flammable.

(3) That refrigerating systems employing F-ll, F-12 or F-114, used for air
conditioning are restricted to the indirect method except that the direct method
may be used in parts of a building so specified in Section C19-98.0 (6) for refriger-
ants other than non-irritant and non-flammable.

(7) That a refrigerating system employing F-ll, F-12 or F-114 shall not be
installed or maintained in a theater and/or motion picture theater unless the en-

Nov., 1943] SENSIBLE USE OF REFRIGERANTS 431

tire system is confined in a fireproof machinery room, used for no other purpose,
and in which no open flame and/or apparatus to produce such open flame shall be
employed, except that Class C systems containing not more than ten pounds of
refrigerant may be installed in a rest room, smoking room, or lounging room pro-
vided in such rooms no open flame or apparatus to produce such open flame shall
be employed.

C19-97.0— Classifications (System)

(a] The total amount of refrigerant common to a system operating through
one or more evaporators, shall be considered the capacity of the system and de-
termine its class.

(6) A Class A system is a system containing one thousand (1000) pounds or
over of refrigerant, or capable of thirty (30) tons capacity or over.

(c] A Class B system is a system capable of less than thirty (30) tons capacity,
or containing less than one thousand (1000) pounds of refrigerant and more than
amounts provided for in a Class C system.

(d) A Class C system is a system containing not more than twenty (20)
pounds of refrigerant.

With the present urge of owners to have their refrigerating systems
operate, especially for comfort cooling even though Freon-12 is not
available under the present War Production Board restrictions, some
suggestions have been made that substitutes be used. The authors
feel that all who are engaged in the servicing and in the supplying of
these substitute refrigerants should carefully understand the hazards
involved both in equipment and in the use of such substitute refrig-
erants for particular locations. We feel it would be much better
to advise the owner of a comfort cooling system, especially in a
theater or a place of public assemblage, that unless he can obtain a
safe refrigerant as now permitted in the ASA Code (and, of course, if
permitted under the Municipal Code in effect), and that unless all the
precautions in these codes can be adhered to strictly, he would be
better off without any refrigerating effect and to depend on his venti-
lation by circulating outdoor air.

It is unquestionably true, we believe, and we have so been advised
by attorneys, that if anyone knowingly substitutes a refrigerant
with a known hazard and life is imperiled or lost, all those performing
the operation are criminally liable.

FILM CONSERVATION METHODS

A SYMPOSIUM*

The conservation of materials is one of the major objectives of all
industry in this war. Particularly is this true in the motion picture
industry, where the enormous requirements of the armed forces
added to the essential civilian demand are creating an unprecedented
consumption of photographic film. A record of the steps being
taken by the various studios to insure the conservation of raw film
stock during sound takes is thus of particular interest at this time.

The following eight papers make up a symposium to which repre-
sentatives of the Sound Departments of as many studios in Holly-
wood contributed their various methods of saving sound-film by
marking, removing, and reassembling non-print sound takes. The
undeveloped film thus reclaimed has been exposed only along one
edge and the unexposed areas may be used for a number of purposes.

This preselection practice, which constitutes a considerable saving
in film raw stock and laboratory processing has been in operation for
some time ; however, the technique varies from studio to studio and
the following papers give detailed accounts of the methods in use at
each studio. The authors contributing to the symposium, in the
order in which their papers appear, are as follows :

"Film Conservation Methods at Universal Studios," by George J. DeMoss,

Sound Dept., Universal Pictures Co., Inc., Universal City, Calif.
"Film Conservation Methods at Republic Studios," by D. J. Bloomberg and J.

Stransky, Sound Dept., Republic Pictures Corp., Hollywood.
"Film Conservation Methods at RKO Studios," by P. E. Brigandi, Sound Dept.,

RKO Radio Pictures, Inc., Hollywood.
"Film Conservation Methods at Columbia Studios," by S. J. Twining, Sound

Dept., Columbia Pictures Corp., Hollywood.
"Film Conservation Methods at Paramount Studios," by I. M. Chambers,

Sound Dept., Paramount Pictures, Inc., Hollywood.

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.
432

FILM CONSERVATION METHODS 433

"Film Conservation Methods at Samuel Goldwyn Studios," by D. A. Newell,

Sound Dept., Samuel Goldwyn, Inc., Hollywood.
"Film Conservation Methods at Walt Disney Productions," by C. O. Slyfield,

Sound Dept., Walt Disney Productions, Burbank, Calif.
"Film Conservation Methods at Warner Bros. Studios," by G. M. Best, Sound

Dept., Warner Bros. Pictures, Inc., Burbank, Calif.

FILM CONSERVATION METHODS AT UNIVERSAL STUDIOS*
GEORGE J. DEMOSS**

To date our sound breakdown system involves utilizing all non-
print takes and short ends salvaged from Daily production, dubbing,
music and sound-effects recording. The non-print takes are seg-
regated as to companies and held pending verification of production
release from the Exchange Office. Inasmuch as the opposite edge
is not exposed during recording, this film is made available for print
stock. The print takes are then assembled and sent to the labora-
tory for Daily processing.

Short ends accumulated from all negative recording are spliced
together in approximately 990-ft lengths and re-used as negative
recording stock for music production, playbacks on musical produc-
tions, silent sound-track for negative cutting, or as direct leader
stock.

In the past the procedure has been to open the recorder door after
each take to identify the scene number by marking through the
center of the film with a soft lead pencil. At this point of operation
the film is also edge-notched with a hand punch to facilitate the
breakdown in the Camera Department. Owing to fogging the
opposite edge of the film and to the allowance made for splicing
losses, the above manual operation results in the loss of three feet of
otherwise available printing stock each time the recorder door is
opened between scenes.

Identification for actual breakdown of the exposed film in the
camera department depends on the sound log, camera card, the
footage, and the edge notch. After segregating the print takes from
the non-print takes it is necessary to remove edge notches, double
scrape, and tape the film so it will survive all mechanical phases of
laboratory processing, such as developing machines, printing ma-
chines, etc.

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.

** Sound Department, Universal Pictures Co., Inc., Universal City, Calif.
434

FILM CONSERVATION METHODS 435

To identify the positive print scene number for cutting purposes
the negative slate, as it appears written on the picture area of the
film, must be transferred to the sound-track area by inking in or by
the use of a stylus in the laboratory. This procedure is necessary
because all sound printing at present involves the use of a matt
which only allows exposure on the actual width of the negative sound-
track.

With the photographic sound slater now in use it is not necessary
to open the recorder door as the scene numbers are predetermined
by the progressive slate number system and are exposed and center-
punched by electrical apparatus. This saves considerable time and
also three feet of film between each two scenes or takes which would
otherwise be fogged.

Film breakdown in the Camera Department is facilitated as the
photographic sound slater eliminates all edge notches by center-
punching the film on the recorder. Inasmuch as the exposed slate
number is not visible until after negative development, the practice
of stopping at each edge notch to visually identify the scene number
under darkroom conditions, and especially the legibility of slates
written in by hand, is now supplemented by the use of a footage
indicator in conjunction with the dial footage log of the sound card.

The use of this new breakdown technique in the Camera Depart-
ment and the elimination of all edge notching reduce the tune pre-
viously consumed in splicing, taping, and all predevelopment physi-
cal handling of the film.

In the laboratory it is no longer necessary to identify the legibility
of, or to transfer written slates, as the scene numbers are now exposed
directly in the negative sound-track area. This avoids the use of
India ink, faulty scratching in of slates by hand, and assures legible,
permanent scene numbers.

Table I reveals that a total of 1,229,000 ft of non-print takes and
short ends became available for re-use during 1942. Also there
was a laboratory processing saving on 1,809,372 ft.

TABLE I

Feet

Negative purchased (all companies) 6,401,375

Print negative developed 4,592,003

Savings on laboratory processing of non-print takes . . . . 1,809,372

436 G. J. DEMoss

Salvage of Short Ends

Feet

(1) Used as music protection* 9,000

(2) Playback negative and leader stock sales 100,000

(5) Sound-effects and silent sound-track negative 76,000

(4) Direct to leader stock 11,000

(5) Used at the laboratory for printing stock (library numbers) . . . 13,000

Total 209,000

Salvage of Non-Print Takes

(1) Used as music protection negative to leader stock* 66,000

(2) Used by the laboratory for printing sound Dailies 954,000

Total 1,020,000

* Used as negative plus subsequent use as leader.

FILM CONSERVATION METHODS AT REPUBLIC STUDIOS*
D. J. BLOOMBERG AND J. STRANSKY**

Previous to 1937 it was customary to record full-length reels of
dubbing on only one side of the film. In 1937 the procedure of
using both sides of the sound negative was adopted. This two-sided
recording is done only if the previous take on one side of the reel
is a non-print take. Unless the recordist gets an immediate print
order on a take he runs the recorder for an additional 25 feet at the
end of the take. The short end is saved and the 25 ft allowance is
enough to rethread the machine and get up to speed. The first take
is not spoiled by this process and may be used up until the time
the standard leaders are cut on. This practice has resulted in no
difficulties in the studio or at the laboratory. The saving for one
year's production is approximately 150,000 feet.

Our next economy was the process of re-using all non-print sound
takes, both from production and scoring. Our slating devices on
the recorders incorporated a film punch which punches a hole in the
center of the sound negative at the same time a scene number is
photographed in the sound-track area. This punch hole, and the scene
footages, enabled the breakdown man to remove only the print takes
from each roll, splice them together, and send them to the laboratory
for developing and printing. By using photographic slates the re-
cording door is never opened for a full 1000-ft roll. The film move-
ment is viewed through a red filter in the recorder door and a red
light is directed behind the film loops.

All the breakdown splices are made with a standard Bell & Howell
negative machine. These splices are taped over with a piece of
waterproof tape for strengthening and greater protection. In four
and one-half years' operation there has not been a single breakage of
a splice.

A flashlight properly filtered is used to read the sound report when
breaking down sound negative.

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.

** Sound Department, Republic Pictures Corp., Hollywood.

437

438 D. J. BLOOMBERG AND J. STRANSKY [J. s. M. P. E.

All film is run through a footage counter set to read in reverse
because of the fact that the rolls are tails out. The film is rolled up
on- two take-up reels, one for the print takes and one for the non-
print takes. This leaves the non-print takes on 1000-ft rolls.

A system of marking the non-print takes is used to make it possible
to find them without difficulty.

Immediately after the picture has been released these non-print
takes are used to print Daily sound and sound-effects tracks.

Owing to the fact that Class B push-pull sound is used, there is
no trouble caused by the breakdown splices in the printing stock.

This breakdown process has other advantages besides film econ-
omy. An approximate reduction of 50 per cent in laboratory ex-
penses and chemicals is accomplished and a noticeable reduction in
film handling marks. Results show an average saving of 130,000
feet of film per month.

In February, 1942, a film punch adapter was put into use on all
action cameras, and the same process of breakdown has been used.
The breakdown room is dark except for a shadow box for the film
reports. The darkened room presents no difficulty to an operator
familiar with the breakdown apparatus and procedure. The num-
bers on the footage counter are painted with luminous paint.

The non-print takes are used by both the Editorial and Sound-
Effects Departments for leaders. Extensive tests were made using
the picture non-print takes as a sound negative and acceptable
results were obtained; however, this is not being done at present.
Using action* non-print takes as leader stock saves buying approxi-
mately 75,000 feet of leader stock per month.

In 1940 an automatic starting device was installed on all the
sound trucks. Its purpose is to light the red lights, ring the "quiet"
bell, start the recorder and camera, expose "sync" marks on picture
and track, put an exposure density on the sound negative, and give a
"speed" signal on the set. At the end of the take the recording
machine and camera are stopped, the red light is turned off, and the
"quiet" bell rings twice. By using this device the timing of each of
these operations is adjusted to use as little film as possible con-
sistent with good operation. It is estimated that at least two feet
of both sound and action are saved on every take. The starting
device can be operated from the stage or the sound-track.

* Picture, not sound-track.

Nov., 1943] FILM CONSERVATION METHODS 439

In 1942 split film (17.5 millimeters) was adopted for all sound-
effects, music, and dubbing prints used in re-recording. The change
necessitated building a film splitting device with a tolerance of =*= 1
mil and converting all re-recording reproducers, sound-effects, and
music moviolas to operate with 17.5-mm track. Two re-recording
reproducers were arranged to run either 35- or 17.5-mm track to
make them available for use with 35-mm sound-track which is still
used in the Editorial Department and for playback tracks and
composites. The annual film saving is approximately 805,000
feet, and the cost of altering the machines was approximately
$5000.

About two years ago, the policy of obtaining an extra print for
playback in case one is damaged was abandoned. All vocals are
recorded on two channels and then temporarily dubbed together for
a playback track and for cutting purposes. Only one print of this
is made but the negative is used as a standby print for the playback
operators. The print is given to the Editorial Department in the
evening of the day it is finished as a playback track. The print is
then used as a work-print by the Editorial Department for cutting
purposes. With this procedure no film is saved by using an acetate
disk for playback. Savings are about 19,000 feet per year.

When playbacks are used on production the master playback
scene is recorded full-length for synchronizing purposes. The re-
maining angles are recorded for the first fifteen feet only. These
recorded tracks are then developed only and the negative is used to
synchronize the playback with the picture. The saving is approxi-
mately 60,000 feet per year.

In April, 1942, re-recording directly from the sound work track
was started and has been continued on all Serials, Westerns, and low
budget pictures. Using the work track as a dubbing print has
given no trouble in obtaining a re-recorded negative that compares
very favorably with pictures recorded from a new negative film and
with new dubbing prints. This again was made possible by Class B
push-pull recording, because of the fact that it is so easy to bloop
out splices, scratches, etc. The saving for one year was 364,000
feet.

In the Camera Department all ends over 75 feet are saved and
used in shooting inserts. This presents no material difficulty in
shooting inserts owing to the fact that scenes are usually very short

440 D. J. BLOOMBERG AND J. STRANSKY U. S. M. P. E.

and no valuable time is lost by loading. This resulted in approxi-
mately 24,000 feet of film saved last year.

All sound short ends over 15 feet long are saved. They are
spliced into 1000-ft rolls of the same emulsion and used to print
sound-effects. The effects are printed on each edge and then the
film is split. The saving for 1942 was approximately 150,000 feet
of full-width film.

In June, 1942, a large surplus of non-print sound takes was found,
and it was decided after numerous tests to use this film as production
sound negative on the low budget productions. This was made
possible again by the use of Class B push-pull which cancels out
nearly all noise from the splices. From June 16, 1942, to January
25, 1943, when the supply returned to normal, 428,635 feet of sound
negative had been saved.

Early in 1941 production leaders at the head and tail ends of
exposed rolls of action negative and sound negative were reduced
from fifteen to five feet. This resulted in a film saving for 1942 of
135,360 feet.

The Sound-Effects Department has adopted the policy of re-using
sound-effects that have previously been assembled without cutting
them from the stock library reel. This usually necessitates using
sound-effects tracks which are much longer than the pictorial scene
in order not to cut the print. While this technique has presented
no problem in dubbing, and the policy has saved a good deal of film
in prints, it has cost more in cutting labor.

As many stock shots as possible are used, particularly in westerns
and serials where the same characters, or posses of a number of men
for chases, run-bys, etc., appear. Wherever practical, dialog in the
script is simplified so that performers do not have trouble in memoriz-
ing and pronouncing.

As far as practical only that part of master scenes which is to be
used in pictures is photographed. All rehearsals on film are elimi-
nated and wherever possible only one take is printed.

Trailer lengths have been reduced to 100 and 150 feet.

Reprints of Dailies are not ordered unless unusable for projection,
and these average less than ten a month. We use only one picture
and sound print for all departments.

No dissolves or fades or montages are ordered until the picture has
been cut. These are all marked with red pencil during the cutting

Nov., 1943] FILM CONSERVATION METHODS 441

process. Fine grains for fades, lap, and dissolves are ordered foi
only five feet each side of the effect.

Trailer tracks and fine grains are ordered from footage to footage.

Only two background process prints are ordered instead of three
or four as was done previously. These prints are left in the Process
Department and used over and over again. All tests are shot with
spliced action, or if possible, stills are used.

FILM CONSERVATION METHODS AT RKO STUDIOS
P. E. BRIGANDI**

RKO Studios have been using the preselection or breakdown system
to conserve film and reduce operating costs since its first use in Holly-
wood. This general procedure has been of considerable saving to
the studio.

However, the amount of stock available for printing purposes
was not sufficient to print all of the sound Dailies at RKO Studios
until the photographic slating device and center punch were added
to the recording machines. Since that time the stock recovery has
been increased by more than fifty per cent. This has resulted in
much greater savings as the amount of stock now available is more
than sufficient to print all sound Dailies. The surplus is used in
numerous ways that will be mentioned later.

The general method used in breakdown is to separate the non-
print takes from the print takes. The non-print takes are then
put into cans and held until the picture has been released. At this
time they are assembled in 1000-ft rolls for printing purposes. To
insure that this stock is free from fog, handling marks, and abrasions,
a number of changes in equipment have been made, as follows:

(1) Safelight windows with protecting covers were installed in the recording
machine door, permitting the operator to watch the loop and check the film travel
in the machine without opening the door and fogging the film.

(2) All of the rollers, magazine, recording machine, and rewind were undercut
and proper clearances provided to prevent damage to the film on the side opposite
the normal negative track position.

(5) Marks on the film from handling were reduced by training the breakdown
personnel to hold the film by the edges as they applied pressure while rewinding
to locate the center punch identifying each scene.

(4) A splicing machine with footage counter and weighted rewinds was in-
stalled hi the breakdown room to prevent cinch marks and abrasions and yet pro-
vide for rapid prepair of the rolls.

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.

** Sound Department, RKO Radio Pictures, Inc., Hollywood.

442

FILM CONSERVATION METHODS 443

The principal use made of the sound-track negative recovered by
preselection is in printing sound Dailies. The next largest use made
of such film is in printing of composite dupe-negatives and prints
after editing is completed on a picture. These are made from the
work-track and action, and are used by the music and cutting de-
partments, etc., in preparing for re-recording. Some other uses are
noted, however; as individual items they constitute a small part
of the total film recovered :

(1) Leader stock (the majority of this is obtained from small rolls that are not
spliced together under a safelight).

(2) Action prints for the trailer department.
(5) Unmodulated track prints.

(4) Sound reprints.

(5) Sound and action stock shot prints for inspection purposes.

(6) Film to be used in cameras or recording machines for various mechanical
checks.

(7) Negative sound-recording stock for production cue tracks. (These are
not printed, but after development are turned over and used as positive. This
procedure is also used with cue tracks or playback tracks shot on good negative.
In either case, the recording machine shutter is set to clear the track area.)

Also, it was planned to use the reclaimed stock for picture Daily
prints. To make this possible, the sound department equipped
the recording machines to handle fine-grain release positive stock
as a sound-recording negative, the film being supplied by the manu-
facturer with negative spools and edge numbers. This was done
about two years ago, but with the conservation program that has
been in effect since the start of the war, the number of non-print
takes made by the production companies has decreased to a point
where the recovery of stock is not sufficient to provide enough for
the action Dailies.

The action negative at the present time is not preselected, but a
great saving has resulted in the elimination of the majority of short
ends. The general practice is to reload the camera only if the re-
maining short end is less than sixty feet.

FILM CONSERVATION METHODS AT COLUMBIA STUDIOS*

S. J. TWINING**

Preselection as a means of film conservation, although important
in itself, can not be discussed without going into the broader aspects
of the general economy of operation. Even where the saving of film
is of prime importance, as it is at the present time, the details
of operation are bound to be modified by other existing circum-
stances.

Those groups which operate their own laboratory as an integral
part of the studio must keep in mind the combined picture of simul-
taneous economies resulting in Camera, Sound, and Laboratory
Departments, since the operations of these departments are inter-
dependent and economies arbitrarily established in one department
without due regard to the effect on the others may result in non-
compensated losses.

On the other hand, studios which have their processing done in a
commercial laboratory have only their own particular economies to
consider and individually the Camera and Sound Departments
may be able to effect greater economies than would be possible were
they required to fit into the larger picture.

In the case of Columbia Studio, film conservation methods must
through necessity be fitted into a larger plan of general economy since
Columbia operates its own laboratory, covering the complete field
of negatives, daily prints and release printing. Keeping these re-
quirements in view, we can now proceed with a description of our
present methods of operation and the reasons therefor.

We will consider first the sound negative. The procedure is as
follows :

As the roll of film passes through the recording machine each take is
manually marked with its proper scene number. A hole is punched

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.

** Sound Department, Columbia Pictures Corp., Hollywood.

444

FILM CONSERVATION METHODS 445

in the center of the film to serve as the synchronizing mark and two
holes are punched to indicate the end of the outgoing scene. The
double punch mark indicates that the film may be broken at this
point without loss of the synchronizing mark or damage to the
take.

The Recorder keeps two sets of records : one, the usual Recording
Report for use of the Laboratory, Editorial, and Sound Departments,
and the other, a report for the Sound Loading Room on which are
listed only the take numbers and corresponding footages, with
printed takes circled. This report is made in large-sized figures
with heavy pencil since it is to be used in the safelight of the loading
room.

All film loading is carried out in a room centrally located and
sufficient personnel is provided so that the preselection breakdown
can also be carried out at this point. Exposed film is taken out of
the magazines and placed on flanged rewinds operated in connection
with a film footage counter and a stapling machine. The breakdown
man has before him the large figured report and as he rewinds the
negative from tail to head through the counter, which gives him a
check on footage, he cuts out the print takes* noted on the report
and places them in one stack. Those sections which are composed
of non-print** takes are placed aside in another stack.

The print takes are then progressively taken up on the rewind
flange and stapled together at the ends to form a continuous roll of
approximately one thousand feet, which is sent to the laboratory for
development and subsequent printing. The rolls of non-print takes
are taped at the ends and each roll is marked on the tape with
the included take numbers. These non-print rolls are then
grouped in cans, appropriately labeled and placed in temporary
storage.

If for any reason prints should be needed at a later date on takes
which were originally designated as non-print, an order is placed
with the Sound Department listing the take numbers required. The
exposed negative is readily located in the temporary storage group
of non-print takes, is taken out, and sent to the laboratory for in-
clusion in the next negative developing run.

Non-print negatives are held in the temporary storage until each

* Also termed, "O.K." takes or selected takes.
** Also termed, "N.G." takes or out-takes.

446 S. J. TWINING [J. S. M. P. E.

particular production has received its final editing at which time
they are released for conversion to other purposes.

For a period in the past it had been our practice to carefully re-
splice this stock in the darkroom and turn it over to the laboratory
for the purpose of making Daily sound prints. This operation pre-
sented some difficulties from time to time.

If the stock which was being currently used for sound negative
was similar in characteristics to that used in the laboratory for
release printing, the sound quality return generally remained on a
satisfactory basis. But if the characteristics of the sound stock
differed materially from that being used in releases, difficulties
occurred. Prints made on converted stock when run at release
developing time resulted in unsatisfactory gamma characteristics.
To correct this condition it was necessary for the laboratory to change
developing time during the release runs, which resulted in lost pro-
duction time for the developing machines.

As a consequence this procedure was eventually abandoned and a
better one substituted. Our present method is to make all Daily
prints, both sound and picture, on spliced stock supplied by the
laboratory from short ends resulting from release printing. This
stock, being from the current release emulsions, returns optimum
quality at all times and can be run through the developing machines
without the necessity of changing developing time.

Non-print sound negative stock is now economically converted to
a number of useful purposes. When rewound so that the opposite
edge can be used for recording purposes, it is employed in making
test runs of sound equipment, toe recorded negatives for synchronous
playback, and sound and music-effect negatives. A considerable
amount is sent to the laboratory and converted into clear leader
which is used by the Foreign Department in their superimposed
title work. Additional amounts are supplied to the Sound Effects
and Editorial Departments for use as opaque leader. At times some
of this stock is sold to outside customers for the purpose of making
sound negatives or prints.

The foregoing remarks on preselection and the conversion of
residual stock have pertained to negative which is used in connection
with production recording. A different type of preselection, if it
may be referred to by that term, is applied to the dubbing operations.
Here we have residual stock which is in continuous 1000-ft
lengths representing unsuccessful or non-print dubbing takes. As

Nov., 1943] FILM CONSERVATION METHODS 447

in the previous case, only that negative which has been designated
for print is sent to the laboratory for development. The non-print
takes are rewound so that the opposite edge is presented for re-
cording and are again used for temporary negatives in connection
with recorded playbacks, when the occasion requires, and for separate
track previews.

In the case of picture negative a different procedure is followed.
Several years ago a limited method of preselection was employed in
the handling of this negative in which only those rolls which con-
tained print takes were sent through the developing processes, re-
sulting in some economy under the conditions which obtained at
that time. As the speed of the negative emulsions was increased,
it was found that when rolls were developed which had been in
storage for a period of perhaps a month or two, such negatives
carried a very bad haze that destroyed their usefulness. It is
possible that this condition could have been improved by a more
elaborate system of storage involving a dependable system of air
conditioning with some overall economy.

Inasmuch as Columbia Studios operates its own laboratory it has
been considered that the economies which might be effected by a
system of preselection of picture negative in the developing operation
would be more than offset by the cost of operation of a breaking-down
system and the attendant risks in handling the negative for the
additional operation. It seems obvious that in the case where the
negative is developed by a commercial laboratory on a cost per foot
basis, money could be saved by a well worked out system of pre-
selection. Economy of film utilization, however, does not seem to
be indicated in this case since the picture negative, once exposed, has
been entirely expended and does not have an opposite edge as in
the case of sound negative which can be used for another record-
ing.

The term "preselection" does not strictly apply to those operations
which are primarily a laboratory function, but it might not be amiss
to mention here a laboratory operation that has resulted in some
economies in film and considerable more in time. This operation
might be termed "presynchronization of the Daily picture and
sound." It had been our practice in the past to bring Daily
picture and sound print out of the laboratory as independent
assemblies after which the two sets of prints were assembled take

448 S. J. TWINING

by take for review. This print synchronizing operation resulted
at times in quite an appreciable film wastage and considerable delay.
The two negatives are now synchronized before printing at which
time all surplus beginnings and ends of takes are trimmed off and
negative groups are assembled of full reel size. When the two
prints come out of the laboratory developing operations they are
immediately available for synchronized review.

FILM CONSERVATION METHODS AT PARAMOUNT
STUDIOS*

I. M. CHAMBERS**

This paper describes our film conservation methods as applied to
sound-film only. We use one edge of the 35-mm film for the original
track, and save all undeveloped takes until the picture is released.
The opposite edge of this film is then used for other sound negatives
or prints as required.

This subject is divided into (a) methods of conserving the stock,
such as prevention of fog, identification of takes, separation of
print takes and non-print takes, and (b) release of non-print takes
for second choice prints and the final release of non-print takes for
re-use.

Prevention of Fog. — The first requirement is that the edge of the
film opposite the original sound-track must not be fogged. This is
accomplished in the recording machine by a shutter mechanism
controlled by the motor system to prevent exposure when the ma-
chine is at rest, or by a relay system controlled by the motor system
to drop the lamp filament to a very low temperature during the rest
period. It is important that excess daylight be prevented from
entering the lens system if the latter method is used. Darkroom
fog is not generally too serious, but if considerable time is used to
make the splices it should not be ignored.

Identification of Takes. — The identification of takes is accom-
plished by the recording operator keeping a very accurate log of the
footage of takes and faithfully punching the film at the start of each
take. Fog sections incurred during reload, bias, motor, or light valve
checks, are identified by having the recording operator roll three
feet of film by hand, with a punch mark before and after each opera-
tion. These fogged sections are removed in the darkroom during
the breakdown procedure.

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.
** Sound Department, Paramount Pictures, Inc., Hollywood.

449

450 I. M. CHAMBERS [J. S. M. P. E.

Separation of Print Takes and Non-Print Takes. — The next opera-
tion is the breakdown or separation of print and non-print takes in
the darkroom. In order to simplify the breakdown the film is first
completely rewound on a motor rewind and appears heads out.
This roll is placed on the left-hand rewind, as shown in Fig. 1, and
threaded through the counter, emulsion up, and the counter set to
zero at the first punch mark.

All print takes are spliced and reinforced with splicing tape, two
inches long by three-quarters of an inch wide, on the celluloid side

FIG. 1. Section of the darkroom showing breakdown equipment.

only and wound on the lower reel of the right-hand rewind which is
equipped with a positive spool. Each scene and take number is
marked on the film in pencil twelve inches in from the punch mark.
Productions are not mixed and all print takes of a production are
wound on one spool until approximately 950 feet is obtained, or
until the production is finished for the day. Each roll is marked
with the production number and the first and last scenes, and a 15-
inch leader is spliced on the end before being sent to the laboratory
for development.

All non-print takes are wound on the upper rewind, equipped
with a negative spool, and are not spliced but held together only with

Nov., 1943]

FILM CONSERVATION METHODS

451

splicing tape. If several non-print takes appear together, only the
first scene and take are marked with pencil for identification. This
process is continued until approximately 950 feet are accumulated on
a roll before another one is started.

Release of Non-Print Takes for Second- Choice Prints. — Release of
non-print takes for second-choice prints is facilitated by storing all
non-print takes in cans with the production number and the first
and last scene numbers marked on the can. In addition, each can is
numbered and every log sheet used in the breakdown of the film in

FIG. 2. Footage counter equipped with air jets to locate punched

holes.

this can is marked with the same number. If the Cutting Depart-
ment requests a print of a non-print take it is a simple matter to
locate the take number and the can number from the log sheets, and
also the location of the take in the can.

Final Release of Non-Print Takes. — All non-print takes are kept
until a release is issued by the Production Department. This is
usually some time after the picture is released in the theater.

Before describing the uses of non-print stock I would like to
review several practical ideas purposely left out so as not to disturb
the continuity of the process.

Finding the punch mark by eye has always been a slow process
even though the footage is known. This difficulty has been elimi-

452 I. M. CHAMBERS [J. S. M. P. E.

nated by forcing a stream of filtered air through a jet against the film
with just enough pressure to produce a hissing sound. When a
punched hole is encountered, the character of the sound is changed
completely for an instant even though the film is traveling at a
fairly high rate of speed. One jet is used when the roll is heads out
and the other when tails out as shown in Fig. 2.

It is not necessary or desirable for the air to flow continuously
but only as a punch mark is approaching. The air is controlled
by a valve, shown in Fig. 3, operated by the left knee of the break-

FIG. 3. Knee-operated valve controlling air to jets in footage

counter.

down man when his footage counter indicates to him that the be-
ginning of the next take is near.

Splice breakage in the negative developer is costly and has been
eliminated by timing each splicing operation to 15 seconds.
An electronic timer controlled by the top right-hand section of the
splicing machine lights a small bull's-eye at the beginning of the
splice and the light is automatically extinguished in 15 seconds —
thus eliminating possible mistakes in timing by the operator.

Splices are made in the normal manner except that cement is not
applied to the scraped section but is applied to the celluloid side of
the film that contacts this scraped section. This is done because

Nov., 1943] FILM CONSERVATION METHODS 453

the base of the splicing machine is heated and the cement dries too
rapidly if applied in the normal manner.

After release all non-print takes, that is, all takes exposed on one
edge only, are spliced together without reinforcing tape into three
groups, as shown in Table I.

TABLE I

AVAILABLE STOCKS AND USES

(A) Sound-Track Exposed on One Side

Size of Roll

(1) Over 500 ft Over 500 ft

(2} Between 200 and 500 ft 1000 ft

(5) Between 20 and 200 ft 1000 ft

(B) Unexposed Stock
(1} Over 500 ft Over 500ft

(2) Between 20 and 500 ft 1000 ft

(2} Non-fine-grain stock Spliced to any length

(5) Variable-area stock Spliced to any length

(-4) Sound-Track Exposed on One Side. — (1) Sections over 500 feet
obtained largely from dubbing negatives are used (a) for prints and
reprints of sound-effects for the Film Library, (b) for prints and re-
prints of mike pick-up takes (a mike pick-up take at this Studio refers
to sound or dialog recorded at the Studio to match picture that was
made silent), and (c) for dupe prints as needed on Technicolor pic-
tures for dubbing, scoring, etc. (2) Sections between 200 and 500
feet obtained both from dubbing and Daily production negative are
used only for dubbing daily prints. (3) Sections between 20 and
200 feet obtained largely from Daily production negative are used
(a) for production Daily prints and reprints, (b) for prints on all cue
tracks for production, (c) for the first dubbing print of a cut negative
(this is a work print only and is not used for final dubbing), and (d)
undeveloped as silent sound-track for dubbing and editing purposes.

(B) Unexposed Stock. — (1) Sections over 500 feet exist at present
only when a complete change of emulsion is made on all recording ma-
chines and several thousand feet of original stock are left. Its uses are
(a) production temporary recording or throw-away track, (b) tern-

454 I. M. CHAMBERS

porary dubbing negatives, (c) temporary mike pick-up negatives,
and (d) production tests.

If insufficient unexposed stock is available then these uses are
transferred to (A-l) above. (2) Sections between 20 and 500 feet
usually cover stock between 20 and 100 feet because all medium
length short ends are used on production. This stock is sent to the
laboratory to be used as black leader for picture cutting, for printing
leaders, and for other print uses such as fade-ins, fade-outs, dissolves,
etc.

(C) Miscellaneous Stock. — This includes (1) all short ends not
used above, (2) non-fine-grained low gamma negative stock used for
white light printing, and (3) short ends of negative stock used on
ultraviolet variable-area recordings. These stocks are all grouped
together and sent undeveloped to the Editorial Department to be
used as silent sound-track in their work-prints and are not to be
used for dubbing.

FILM CONSERVATION METHODS AT SAMUEL GOLDWYN

STUDIOS*

D. A. NEWELL**

Conservation of sound-track film at Samuel Goldwyn Studios
operates as follows :

Each roll of film as it is threaded on the recording machine is
given a magazine card. On this card appears the production num-
ber, date, machine number, emulsion, magazine number or numbers,
and the operator's name. This card has three columns in which are
written the track number, the accumulated footage, and the take
footage. Enough room is also provided for remarks pertaining to
this particular roll of film — such as missed punches and slates or
special laboratory handling. Special laboratory handling may
include such items as two or more prints on a certain track, a change
in gamma of either negative or print, or a develop-only order.

An externally operated punch is located at one end of the re-
corder just before the film passes into the exposed side of the maga-
zine. This punch cuts a 5/ie-inch hole in the film approximately
Vie inch from the sprocket-hole. Some care had to be taken with
the design of this punch in order to keep the punchings away from
the exposed portion of the film. The plunger is light sealed and
altogether is quite a simple set-up. Each take is, of course, punched
at the beginning.

The slating device carries four rows of movable figures. In
addition to nought to nine there are also provided prefixes for scor-
ing, dubbing, sound-effects, "wild" lines, and tests. This device
is also externally mounted and operated thus allowing the entire
roll of film to be run through the machine without fogging. A
starting mark is fogged on the film by momentarily opening the lamp
shutter while the slate is being photographed. Provision is also
made in the slating set-up to include the production number and also
whether or not the track is preequalized.

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1934.

** Sound Department, Samuel Goldwyn, Inc. Hollywood.

455

456 D. A. NEWELL

After each roll of film is exposed the magazine file card is placed
in its holder and taken to the breakdown room. The film is then
broken down. The safety lights in this room are equipped with
OA series filters and 10- watt lamps delivering a relatively bright
light which, with ordinary recording stock, has been found to be safe
during handling time. Each take is properly identified and wrapped
in black lightproof paper and placed in ordinary film cans which
are stored in consecutive order for possible later processing.

Approximately sixty days after release of the picture the un-
wanted non-print takes are assembled into 1000-ft rolls and
used for printing Dailies. In assembling these rolls the longer
scoring, dubbing, and Daily takes are used and the shorter takes
are set aside for leader and dubbing fill-in stock.

This system has been in operation for over ten years and has
saved noticeably in two instances — first, in the cost of negative
development and, secondly, in the partial cost of print stock. Table
I illustrates savings on four typical pictures.

TABLE I

To Laboratory for

Production Negative Exposed Negative Developed Re-use in Printing

No. Feet Feet Feet

(5900) 208,000 137,000 30,000

(108) 1,107,000 538,000 182,000

(4500) 235,000 122,000 102,000

(5600) 443,000 255,000 102,000

We found that owing to variation in transmission care must be
taken to keep the same emulsion together for print stock. Also
the splicing machine requires more frequent attention in order to
minimize laboratory trouble from broken patches.

FILM CONSERVATION METHODS AT WALT DISNEY
PRODUCTIONS*

C. O. SLYFIELD**

About 1933, it was decided in the Sound Department of Walt
Disney Studios that some procedure should be established whereby
only "selected" takes would be sent to the laboratory for processing.
With this in mind, the following system was adopted :

At the time of recording, the take numbers are punched in the film
and a notch, similar to a timing notch, is punched on the edge of the
film to assist the film breakdown man in locating the take number.
After recording, the film is taken into the darkroom and broken
down into "selected" and "hold" takes under a safelight. On each
roll of film, two lamp tests are made. One of these tests goes to the
laboratory with the "selected" takes and the other is held with the
"hold" takes.

In case any of the "hold" takes are later sent to the laboratory
for processing, all or part of this second lamp test is included with
the film so it may be developed by the laboratory to set the develop-
ing time. The "hold" takes are held for a period of thirty days at
the end of which time they are turned over to the Test Camera De-
partment or Cutting Department. The Test Camera Department
makes use of the long takes for photographing the original pencil
animated drawings for test reels. The sound-track on the edge of
the film is blocked off by the projection aperture, so is not seen.
The Cutting Department uses a great deal of film for leader in
animation tests and re-recording reels.

About a year ago we started photographing the take numbers in
the sound-track area of the film, so we now have no visible numbers
for the breakdown man. However, we still notch between takes so
the breakdown becomes only a problem of accurately counting the
notches from the end of the roll.

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.

** Sound Department, Walt Disney Productions, Burbank, Calif.

457

458 C. O. SLYFIELD

Since the institution of this breakdown procedure the Studio
has saved many thousands of dollars as the film itself is salvaged
for further use and the cost of processing "hold" takes is elimi-
nated. So far, we have never been able to completely supply the
needs of the Test Camera and Cutting Departments.

FILM CONSERVATION METHODS AT WARNER BROS.

STUDIOS*

G. M. BEST**

In conservation of sound-track negative raw stock at Warner
Bros, identification of the start of each take is made by the recording
machine operator, who nicks the edge of the negative with a special
punch. This involves opening the door of the recording machine,
but in RCA equipment only one foot of film is fogged, resulting in a
minimum of waste. Scene and take numbers are marked on the
film with soft lead pencil, these marks being plainly visible to the
breakdown operator, who passes the film through his gloved hand
and stops at each nick. A recording card accompanies each roll
that passes through the recording machine, and on this card the
recorder marks whether the scenes are non-print, hold or print.
All non-print are marked with an "X," while hold or print takes are
marked with the letter "O," followed either by the words "print,"
or "hold."

All breakdown and splicing are done by the laboratory where a
special dust-free room equipped with rewinds, safelights, storage
racks, and standard Bell & Ho well splicing machines is available at
all times. The laboratory sends only the print takes through the
developer, retaining the non-print takes on a large rack in the break-
down room until 72 hours after they have been received, at which
time, if no order for development of any of them has been received
through regular channels, they are spliced into 1000-ft rolls and
sent to the printing room. Hold takes, which amount to about 15
per cent of the total footage shot on the average Class A picture,
are sent to the vaults and stored away until a committee representing
the main office in New York has screened the completed picture,
and has approved it for release. A copy of their letter of approval
is routed through the proper channels and authorization to splice

* Presented before the Pacific Coast Section meeting, Hollywood, May 25,
1943.

** Sound Department, Warner Bros. Pictures, Inc., Burbank, Calif.

459

460 G. M. BEST U. S. M. P. E.

the hold takes is then issued. This may take place many months
before the picture is released and certainly never after the release
date. This method reduces to a minimum the amount of film stored
at any time, and provides for immediate use of fresh spliced negative
while the emulsion is still new.

The splicing of the non-print takes is done by the breakdown
operator during those hours after he has completed his breakdown
work, and also by other members of the laboratory personnel when
they can be spared for the work. Spliced negative is used for (a)
all sound-track Dailies, regardless of their character, and (b) scoring
composite dupe negative and two prints therefrom.

This uses all the available spliced negative, and where there is
insufficient stock of this type for printing the Dailies, new stock is
used for them. The set-up at Warner Bros, provides a composite
dupe print of the cutting picture and sound prints for the Music
Department and another for the Dubbing Department, so that the
cutting prints are not used after the picture is approved for scoring
and dubbing. This requires a footage equal to three times the
length of the picture, and attempts have been made to use the dupe
negative as a print for one of the departments, but so far with little
success.

All separate sound-track prints, regardless of their purpose, have
an exposure 150 mils wide of opaque density, printed on the edge
opposite the sound-track. This permits the use of all prints, after
they have served their original purpose, as black leader for the
Dubbing Department. Thus all prints which would ordinarily be
discarded, trims, transmission tests which are run once and then
thrown away are all used as black leader. The Dubbing Depart-
ment splices this film into 1000-ft rolls and reverses the direction,
issuing it to the effects cutters as required. Tracks which are stored
away for several years and then destroyed when there is no further
possibility of using them are salvaged to the extent of cutting out
the long, unbroken sections and sending them through the wash tanks
in the laboratory to give the film new life, and are used again as black
leader. In this way, no raw stock of any kind is ever fogged and
developed as black leader. Each sound-track printer has a black
leader fogging device as a built-in feature, and its function is auto-
matic and constant. The question might arise as to what would
happen if the printing machine operator left this light on while
printing composite prints. The answer is that it has been done,

Nov., 1943] FILM CONSERVATION METHODS 461

but the same man never does it twice for obvious reasons. Hence,
little trouble has resulted from this fogging light while printing
composite prints, and its presence on the printer can be disregarded.

Short ends of sound-track negative that have not been run through
the recording machine are spliced into 1000-ft rolls by the Sound
Department darkroom attendant in his spare time. They are
segregated as follows :

(1) Rolls having splices from 10 to 25 feet apart; playbacks from stages for
cutting purposes only.

(2) Rolls having splices from 50 to 100 feet apart; screen tests and Sound
Department transmission tests.

(5) Rolls having splices from 200 feet up; narrations for shorts, cartoons,
etc.; sound-effects.

Recording cards for this type of stock are of a special color, and
are marked "Spliced Negative." Recordings of this stock are put
through the developer last, after all the Dailies have passed through
so that if there is a defective splice, no work that represents a large
investment is lost. In the three years in which this system has
been in use, there have been but two breaks in the developing machine
because of a defective splice, and neither caused any serious loss of
time or money.

It might be noted here that Warner Bros. Laboratory uses the
metal patch method of splicing negative passing through the de-
veloping machine. This requires that the developed negative be
broken down and reassembled with standard Bell & Howell splices
before it can be printed.

MEMBERS OF THE SOCIETY

LOST IN THE SERVICE OF

THEIR COUNTRY

FRANKLIN C. GILBERT

ISRAEL H. TILLES

S. M. P. E. TEST-FILMS

These films have been prepared under the supervision of the Projection
Practice Committee of the Society of Motion Picture Engineers, and arc
designed to be used in theaters, review rooms, exchanges, laboratories,
factories, and the like for testing the performance of projectors.

35-Mm. Sound-Film

The recorded frequency range of the voice and music extends to 10,000
cps. ; the constant-amplitude frequencies are in 15 steps from 50 cps. to
10,000 cps. Price $37.50 each.

35-Mm. Visual Film

16-Mm. Sound-Film

The recorded frequency range of the voice and music extends to 6000
cps.; the constant-amplitude frequencies are in 11 steps from 50 cps. to
6000 cps. Price $25.00 each.

16-Mm. Visual Film

An optical reduction of the 35-mm. visual test-film, identical as to
contents and approximately 225 feet long. Price $25.00 each.

SOCIETY OF MOTION PICTURE ENGINEERS

HOTEL PENNSYLVANIA

NEW YORK, N. Y.

Statement of the Ownership, Management, Circulation, Etc., Required by the

Acts of Congress of August 24, 1912, and March 3, 1933, of Journal of the Society

of Motion Picture Engineers, published monthly at Easton, Pa., for October 1,

1943.

State of New York \ Qe

County of New York / Sk

Before me, a Notary Public in and for the State and county aforesaid, person-
ally appeared Harry Smith, Jr., who, having been duly sworn according to law,
deposes and says that he is the Editor of the Journal of the Society of Motion
Picture Engineers and that the following is, to the best of his knowledge and
belief, a true statement of the ownership, management (and if a daily paper,
the circulation), etc., of the aforesaid publication for the date shown in the above
caption, required by the Act of August 24, 1912, as amended by the Act of
March 3, 1933, embodied in section 537, Postal Laws and Regulations, printed
on the reverse of this form, to wit:

1. That the names and addresses of the publisher, editor, managing editor,
and business managers are :

Name of — Post Office Address —

Publisher, Society of Motion Picture Engineers, Hotel Pennsylvania, New York,

N. Y.

Editor, Harry Smith, Jr., Hotel Pennsylvania, New York, N. Y.
Managing Editor, None.
Business Manager, Harry Smith, Jr., Hotel Pennsylvania, New York, N. Y.

2. That the owner is: (If owned by a corporation, its name and address
must be stated and also immediately thereunder the names and addresses of
stockholders owning or holding one per cent or more of total amount of stock.
If not owned by a corporation, the names and addresses of the individual owners
must be given. If owned by a firm, company, or other unincorporated concern,
its name and address, as well as those of each individual member, must be given.)
Society of Motion Picture Engineers, Hotel Pennsylvania, New York, N. Y.
Herbert Griffin, President, 133 E. Santa Anita Ave., Burbank, Calif.

E. Allan Wifflford, Secretary, 30 East 42nd St., New York, N. Y.
M. R. Boyer, Treasurer, 350 Fifth Ave., New York, N. Y.

3. That the known bondholders, mortgagees, and other security holders owning
or holding 1 per cent or more of total amount of bonds, mortgages, or other
securities are: (If there are none, so state.)

None.

4. That the two paragraphs next above, giving the names of the owners,
stockholders, and security holders, if any, contain not only the list of stockholders
and security holders as they appear upon the books of the company but also,
in cases where the stockholder or security holder appears upon the books of the
company as trustee or in any other fiduciary relation, the name of the person or
corporation for whom such trustee is acting, is given; also that the said two
paragraphs contain statements embracing affiant's full knowledge and belief
as to the circumstances and conditions under which stockholders and security
holders who do not appear upon the books of the company as trustees, hold stock
and securities in a capacity other than that of a bona fide owner; and this affiant
has no reason to believe that any other person, association, or corporation has
any interest direct or indirect in the said stock, bonds, or other securities than
as so stated by him.

5. That the average number of copies of each issue of this publication sold
or distributed, through the mails or otherwise, to paid subscribers during the
twelve months preceding the date shown above is : (This information is required
from daily publications only.)

HARRY SMITH, JR., Editor, Business-Manager.
Sworn to and subscribed before me this 4th day of October, 1943

(Seal) Jesse F. Tompkins

Notary Public, Clerk's No. 39T44,
N. Y. County. Reg. No. 4T93
(My commission expires March 19, 1944)

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

VOLUME XLI • • • DECEMBER, 1943

CONTENTS

PAGE

RCA Audio Chanalyst — A New Instrument for the
Theater Sound Engineer

A. GOODMAN AND E. STANKO 467

Editing and Photographic Embellishments as Applied
to 16-Mm Industrial and Educational Motion
Pictures L. SHERWOOD 476

Recent Developments in Sound Control for the Legit-
imate Theater and the Opera H. BURRIS-MEYER 494

Sound Control in the Theater Comes of Age

H. BURRIS-MEYER 500

Recent Laboratory Studies of Optical Reduction
Printing R. O. DREW AND L. T. SACHTLEBEN 505

Current Literature 514

Society Announcements 515

Index of the Journal, Vol. XLI (July-December, 1943) :
Author Index 518

Classified Index 521

(The Society is not responsible for statements of authors.)

JOURNAL OF THE SOCIETY OF
MOTION PICTURE ENGINEERS

HARRY SMITH, JR., EDITOR
ARTHUR C. DOWNES, Chairman

Board of Editors

JOHN I. CRABTREE ALFRED N. GOLDSMITH EDWARD W. KELLOGG
CLYDE R. KEITH ALAN M. GUNDELFINGER CHARLES W. HANDLEY

ARTHUR C. HARDY
Officers of the Society
** President: HERBERT GRIFFIN,

90 Gold Street, New York, N. Y.
** Past-President: EMERY HUSE,

6706 Santa Monica Blvd., Hollywood, Calif.
** Executive Vice-P resident: LOREN L. RYDER,
5451 Marathon Street, Hollywood, Calif.
^Engineering Vice-President: DONALD E. HYNDMAN,

350 Madison Avenue, New York, N. Y.
** Editorial Vice-President: ARTHUR C. DOWNES.

Box 6087, Cleveland, Ohio.
* Financial Vice-President: ARTHUR S. DICKINSON,

28 W. 44th Street, New York, N. Y.
** Convention Vice-President: WILLIAM C. KUNZMANN,

Box 6087, Cleveland, Ohio.
^Secretary: E. ALLAN WILLIFORD,

30 E. 42nd Street, New York, N. Y.
^Treasurer: M. R. BOYER,

350 Fifth Ave., New York, N. Y.
Governors

*H. D. BRADBURY, 411 Fifth Avenue, New York, N. Y.
*FRANK E. CARLSON, Nela Park, Cleveland, Ohio.
*ALFRED N. GOLDSMITH, 580 Fifth Avenue, New York, N. Y.
*A. M. GUNDELFINGER, 2800 S. Olive St., Burbank, Calif.
'CHARLES W. HANDLEY, 1960 W. 84th Street, Los Angeles, Calif.
*EDWARD M. HONAN, 6601 Romaine Street, Hollywood, Calif.
*JOHN A. MAURER, 117 E. 24th Street, New York, N. Y.
**WILLIAM A. MUELLER, Burbank, Calif.

**HOLLIS W. MOYSE, 6656 Santa Monica Blvd., Hollywood, Calif.
**H. W. REMERSHIED, 716 N. La Brea St., Hollywood, Calif.
**JOSEPH H. SPRAY, 1277 E. 14th Street, Brooklyn, N. Y.
**REEVE O. STROCK, 195 Broadway, New York, N. Y.

*Term expires December 31, 1943.
**Term expires December 31, 1944.

Published monthly at Easton, Pa., by the Society of Motion Picture Engineers.

Publication Office, 20th & Northampton Sts., Easton, Pa.

General and Editorial Office, Hotel Pennsylvania, New York, N. Y.

Entered as second-class matter January 15, 1930, at the Post Office at Easton,

Pa., under the Act of March 3, 1879. Copyrighted, 1943, by the Society of Motion

Picture Engineers, Inc.

RCA AUDIO CHANALYST

A NEW INSTRUMENT FOR THE THEATER SOUND ENGINEER*
ADOLPH GOODMAN AND EDWARD STANKO**

Summary. — Proper service and maintenance of theater reproducing equipment
has been an important consideration in bringing the art to its present high state of
development. Improved service instruments and techniques have been necessary to
keep pace with the rapid improvements made during the past decade and will continue
to be important factors in the post-war period. The instrument described here is a
new departure in the field of service as applied to theater equipment.

Parallel with the advances in projector and sound equipment design
has been the improvement in the sound service engineers' technique
and equipment. As new developments occurred in the art, more pre-
cise adjustments of the sound-reproducing apparatus were required to
give the audience the realism demanded by modern recordings. The
service organization has responded to the more rigid requirements
with improved tools and technique. Many new instruments were
made available, such as the cathode ray oscillograph, the special
power level indicator, the high impedance analyzer, and the flutter
indicator. In addition, new types of test films were developed to
provide complete overall check and calibration of the sound appara-
tus.

With the many new instruments available, there came a demand for
a light, compact test instrument that would incorporate the functions
of many of the meters now carried by the engineer. Through the
facilities of the RCA Engineering Division and the practical knowl-
edge gained by field engineers, the requirements for such an instru-
ment were met by the RCA audio chanalyst.

Not only does this instrument fit the needs for compactness and
efliciency, but it offers an entirely new service technique, known as
audio signal tracing. With existing methods, tests are performed on
the complete system or units under static conditions. The new

* Presented at the 1942 Spring Meeting at Hollywood.
** RCA Service Co., Inc., Camden, N. J.

467

468

A. GOODMAN AND E. STANKO

[J. S. M. P. E.

method of signal tracing permits tests and checks to be performed on
the units, while each unit is in operation under dynamic conditions.

With this instrument it is possible to locate sources of noise in
audio circuits, determine cause of inoperative amplifiers, and locate
the source of audio oscillation. In addition, it will measure power
output in watts, a-f, a-c and d-c voltages, over-all gain, gain per
stage, impedance, capacity, and resistance. It will supply fixed
audio frequencies. It may be used to check phase inverter circuits,

FIG. 1.

power supply units, microphones, phonograph pick-ups, and numer-
ous components in the sound system.

The audio chanalyst, which is housed in a metal case, consists es-
sentially of two calibrated amplifiers, a permanent magnet speaker
with associated amplifier, an audio-frequency oscillator and an ex-
tremely sensitive electronic voltmeter. The complete unit weighs
35 Ibs and the dimensions are: height, 125/s in.; width, 18 in.; depth,
95/8 in. A source of power of 115 volts a-c, 60 cycles, is required for
operation of the instrument. All controls and indicator devices are
mounted on the front panel, easily accessible for operation. Fig. 1

Dec., 1943]

RCA AUDIO CHANALYST

469

is a front view of the complete unit. Fig. 2 is a view of the interior,
and Fig. 3 shows the connecting cables for the audio chanalyst.

Amplifier channel A is a three-stage high gain, resistance-coupled
amplifier, the output of which is impressed on an RCA 6E5 Magic
Eye tube. This amplifier is provided with two calibrated controls
for adjusting the signal level. Amplifier channel B is a single-stage
resistance-coupled amplifier, the output being rectified by one diode

FIG. 2.

of an RCA 6H6 tube, and the signal impressed on an RCA 6E5 Magic
Eye tube. This amplifier is also provided with two calibrated signal
controls. The speaker channel amplifier is a single-stage amplifier
transformer coupled to a permanent magnet speaker.

The electronic voltmeter incorporates two RCA 6G6 tubes in a new
push-pull balanced electronic circuit. The RCA 6X5 is used for
rectifying a-f and a-c signals. The input resistance of this meter for
d-c ranges is 20 megohms, and 1 to 2 megohms for a-f and a-c ranges.
The a-c voltmeter is furnished with a decibel scale having a range from
-20 to +9.2 db (0.006 milliwatt level across 500 ohms). The total

470

A. GOODMAN AND E. STANKO

[J.S. M. p. E.

over-all range when used in conjunction with the channel amplifiers
is -80 to +49 db in 11 ranges.

The sensitivity of the electronic voltmeter is 5 volts full scale on
both a-c and d-c and has 8 ranges permitting voltage measurements
to be made on circuits as high as 1000 volts. It will also measure
resistance values to 400 megohms and impedance values to 400,000
ohms. The frequency characteristic is flat up to 20,000 cycles
per second. A fixed frequency audio oscillator provides the following

FIG. 3.

frequencies: 60, 150, 400, 1000, 2500, 5000, and 10,000 cycles per
second. A tapped output transformer allows selection of the follow-
ing impedances for matching line and amplifier input circuits:
250, 500, and 5000 ohms on balanced lines and 62.5, 125, and 1250
ohms on one-side grounded circuits. One RCA 5Z4 tube is used as a
rectifier, and an RCA VR-150 regulator tube is used to stabilize the
B supply voltage for the oscillator (Fig. 4).

When using the audio chanalyst for signal tracing, the various units
are arranged so that channel A amplifier, and its associated Magic
Eye, may be used individually or in cascade with channel B, and its

Dec., 1943]

RCA AUDIO CHANALYST

471

472

A. GOODMAN AND E. STANKO

[J. S. M. P. E.

Dec., 1943] RCA AUDIO CHANALYST 473

Magic Eye, or a combination of A , B, and speaker channels, can be
used simultaneously with the electronic voltmeter. Thus, the pres-
ence or absence of a signal can be observed visually at the output of
either channel A or channel B amplifiers, or it can be measured elec-
trically by the meter, and at the same time, heard aurally on the
speaker. This combination of visual, quantitative measurements,
and aural signal reproduction will instantly enable the engineer to
determine where the signal is, and where it diminishes in strength, and
how much (Fig. 5).

In audio-signal tracing and trouble localizing, the amplifier under
test is set up for normal operation, and the power turned on so that all
measurements can be made under actual operating conditions. A
400-cycle signal from the audio-frequency oscillator is fed to the in-
put of the amplifier under test. If a high-gain amplifier is being
checked, the signal should be further reduced by an attenuator be-
tween the oscillator and amplifier input.

Channel B amplifier may be connected to the output of the ampli-
fier being checked. When the signal at the output of the amplifier
under test is absent, distorted or noisy, as indicated by channel B
amplifier Magic Eye, the probe on channel A amplifier is used to lo-
cate the point where the signal departs from normal. This can be
detected by observing the amplified signal as the signal tracing probe
is used to trace the signal from the amplifier input throughout the
various parts of the circuit, step by step. The speaker channel am-
plifier may be used to check the signal at the output of either A or B
channels by means of a switch provided for this purpose.

The electronic voltmeter can be used to check the over-all signal or
gain of a single stage while the source of trouble is being located.
When the trouble has been traced and localized to some particular
part of the circuit, or component, measurements can then be made to
determine the departure from normal by measuring the voltage, cur-
rent, resistance, capacitance and inductance of the component sus-
pected of causing the trouble. All of these tests can be made without
resorting to other instruments as the units have been so designed and
arranged that they can be used for making individual measurements.

When tracing signals in amplifiers requiring more channel gain
for probing, both A and B channels can be connected in cascade.
By means of calibrated gain controls on the audio chanalyst, and cali-
brated meter scale on the electronic voltmeter, the gain per stage, or
over-all gain, can be measured in voltage gain or directly in db.

474 A. GOODMAN AND E. STANKO [J. S. M. P. E.

To locate noise in an amplifier, it is not necessary to use a signal
from the audio oscillator. The noise itself can be considered a signal,
and the probing amplifier gain controls are set for maximum gain.
The procedure for locating noise is practically the same as that used
in signal tracing. If there is noise present at the point where the
probe is located, the noise can be observed by a flickering of the Magic
Eye or heard on the speaker. Point-to-point checking is followed
through until the source of the noise is located.

Checking push-pull stages of an audio amplifier is a comparatively
simple test. The same set-up is used as for signal tracing and noise
detecting. The signal is traced from the plate of the preceding tube
through the push-pull transformer to the grid of each push-pull
stage. The signal voltage at each grid should be the same if the am-
plifier stage is operating normally. Inequality of signal voltage, or
absence of a signal at either grid, indicates trouble somewhere in the
circuit.

If a phase inverter circuit is operating normally, the signal voltage
at each grid of the phase inverter tube will be the same. The signal
voltage at the plates of the same tube will be the same as at the
grids of the following output tubes. Any variation in signal level at
any of the above-mentioned points should be investigated. Noise
and hum levels can be checked using either the Magic Eye indicators,
or the electronic meter, and speaker channel. Hum on the Magic Eye
will be indicated by a fuzziness of the image, or it can be measured by
the electronic voltmeter.

Intermittent operation of an audio amplifier is probably one of the
most difficult troubles to locate. This intermittent condition may
be difficult to trace with ordinary test equipment because instruments
now used will not permit simultaneous signal checking at several dif-
ferent points in the amplifier without affecting the operation of the
amplifier being checked.

With channel A, channel B, speaker channel, and electronic volt-
meter of the audio chanalyst connected to four different sections of the
amplifier under test, any intermittent condition can be isolated
quickly. That section of amplifier in which a change of signal level
occurs is indicated by either of the Magic Eyes or the electronic volt-
meter, or signal output of the speaker channel.

Phonograph pick-up units can be checked easily by connecting them
to either A amplifier, or B amplifier input and checking the frequency
response with a constant frequency record. Distortion can be

Dec., 1943] RCA AUDIO CHANALYST 475

checked audibly by switching the speaker channel amplifier to output
of either A or B channels.

Capacitance and impedance measurements are made with the elec-
tronic voltmeter in conjunction with the audio-frequency oscillator.
Calibrated charts are provided so that all tests can be converted to
actual values. Suitable cables are supplied as part of the audio
chanalyst for making all tests and interconnections between it and the
unit, or units, to be checked. The audio chanalyst is not limited to
the uses described in this paper. There are many other tests which
can be performed and in practical application, no doubt many new
uses may be found.

The compactness and flexibility of the RCA audio chanalyst, to-
gether with the many functions that it will perform, place this instru-
ment far ahead of any test equipment that has been previously used
for locating audio amplifier troubles.

EDITING AND PHOTOGRAPHIC EMBELLISHMENTS AS

APPLIED TO 16-MM INDUSTRIAL AND EDUCATIONAL

MOTION PICTURES*

LARRY SHERWOOD**

Summary. — Procedures and equipment used to edit 16-mm industrial and educa-
tional motion pictures are described. Various types of effects are explained and ex-
amples given of some use to eliminate excessive film footage.

Due to a long succession of involved circumstances, 16 mm has
been regarded as a stepchild of 35 mm. The only logical reason
must be that the film area is smaller, therefore everything connected
with 16 mm must be smaller. Editing equipment, camera adequacy,
projector efficiency; yes, even production technique must be in
direct proportion to the film area.

When stated thusly, it seems almost ridiculous. Certainly, such
reasoning is fallacious.

If one had an 8 X 10-in. portrait camera and desired to build a
35-mm miniature camera, would the procedure be merely to build
the "mini" camera along the same lines as the portrait camera, with
but one thing in mind — reduce in size the elements involved? Yet,
regrettable as it may seem, this is what has happened to a large
degree to 16 mm.

Due to these circumstances, those of us who are utilizing 16 mm for
something more than a hobby have found it necessary to become
protestants and attempt to develop or redesign much of the equip-
ment, and likewise evolve a technique of procedure which will satisfy
the needs of a relatively new and growing industry.

It must not be construed that what has been done is final, perfect,
or in every instance completely satisfactory. Yet, it can be said
without fear of contradiction that the methods, various types of
equipment and procedures that have been developed, work.

Therefore, it is without prejudice or any attempt to convey a
finalty in these factors that the following are commended to you.

* Presented at the 1942 Fall Meeting at New York.
** Director of Productions, The Calvin Company, Kansas City, Mo.

476

PHOTOGRAPHIC EMBELLISHMENTS

477

First, let us study in some detail a satisfactory 16-mm editing room
and equipment.

The room should be small, perhaps 9 ft sq, with soft green walls,
and well ventilated.

On the walls are fastened tiers of 1 X 2-in. boards parallel to the
floor and into which nails or pegs 3J/2 in. apart are driven. By thus
spacing the nails and boards 100-ft 16-mm projection reels can be
placed upon them, as shown in Fig. 1.

JiOTi

FIG. 1. Wall rack to hold 100-ft 16-mm reels.

The editing table, shown in Fig. 2, is desk high and well lighted.
Attached to the back side of the table is a baffle board. In the left
side in rows have been driven ten or twelve pegs or nails. These
nails are arranged with sufficient room between them so that normal
100-ft reels can be placed upon them.

On top of the back bafflle board is a small speaker. The table
contains two drawers, one on each side. The left drawer holds an
amplifier which is connected to the speaker and to a sound head taken
from a Victor standard 16-mm projector, Fig. 3. This particular

478

L. SHERWOOD

[J. S. M. p. E.

sound head is used because it has proved by trial and error to be
easy to handle and does the job of a good "squawker." The film
can be easily moved back and forth across the drum in order to pick
out particular words or phrases to form a guide for the cutting proc-
ess.

This sound head is attached to a Bell and Howell 16-mm silent
projector, both of which are synchronized so that the sound-track

FIG. 2. Editing table.

and the film, when finally edited, can be checked carefully and
accurately before sending to the laboratory for printing.

At each end of the editing table, four or six 800-ft take-up reels
are mounted on shafts which allow them, when turned, to travel
synchronously.

The synchronizing machine consists of four or six sprockets with
the teeth on one side, as seen in Fig. 4. The sprockets are mounted
securely on a shaft. This machine utilizes either silent or sound stock.

Fig. 5 shows the "editor," a standard Craig. It is suggested that
the right spool under which the film passes be moved nearer to the

Dec., 1943]

PHOTOGRAPHIC EMBELLISHMENTS

479

edge of the viewer. This lessens the tension on the film as it is being
moved back and forth. Also, the roller on the left side, which creates
the pressure against the film, should have attached to it a small
lever or handle so that it can be moved up and down to facilitate
removing the film. A Craig operates on the principle of a prism,

FIG. 3. Projector.

which enables the editor to see, with no confusion, each particular
frame. This is very essential in cutting on action or movement.

It is also recommended that a foot switch be installed for better
control of the light source thereby lessening the possibility of burning
the film.

The splicer, shown in Fig. 6, is a Griswold 16-mm Junior — and there
is that word "junior" again. When properly adjusted, it makes a

480

L. SHERWOOD

[J. S. M. P. E.

very fine, thin, yet strong and durable splice which does not show
in projection.

A pair of good sharp scissors is a highly essential tool of a good
editor. Ordinary emery boards, the very same used by any mani-
curist, are also a very efficient tool of the editor. There are various
methods of removing emulsion from film; however, we have found
that by scraping dry with an emery board which has been clipped off

FIG. 4. Six-sprocket synchronizing machine.

with the scissors at an angle after each use, the emulsion can be re-
moved completely and quickly for the splicing process.

With a small bottle of Eastman cement clamped on the side of the
table to the right of the editor, a footage counter, and four other
take-up reels, we have an efficient set of tools to begin the job of
editing. A handy bin to hold 100-ft projection reels will facilitate
the speed.

Before we begin a detailed discussion of editing, let us define it
with regard to motion pictures. "Editing is an art — and we must
call it an art — of piecing together with a splicer, an emery board, some

Dec., 1943]

PHOTOGRAPHIC EMBELLISHMENTS

481

imagination, and a little cement a series of photographic scenes to
form a clear, concise, and easily understood explanation of a particular
subject."

In the industrial and educational motion picture field it is neces-
sary to utilize various types of editing technique, such as all syn-

FIG. 5. Standard Craig editing projector.

chronous "shows," straight cut, or other types such as shows con-
taining trick effects, sound effects, musical background, etc. Each
requires a different type of handling. However for clarity let us as-
sume that we are to edit a 16-mm color production with musical
background, synchronized sound effects, narrator track, and with a
few synchronized sequences. We obviously do not want to edit with
original film of any type. Inasmuch as edge-numbering has not yet,
we regret to say, become uni versa 1, we must develop a technique for

482

L. SHERWOOD

[J. S. M. P. E.

marking film. To do this, we begin with script or camera report
made in the field at the time of taking the pictures; each scene is
naturally numbered. We begin with any reel of the original film
and edit out the scenes to be used in the picture, winding at the same
time on a rewind, all those scenes we are not going to use, or as we
choose to call them, the "overs."

As we identify all of our good takes, we wind each separate scene

FIG. 6. Griswold Junior splicer.

on a 100-ft reel, stick a piece of Scotch tape on the end of it, lap it
back over the side of the reel and print the scene number or descrip-
tion of that particular scene on the tape. Reel by reel, as each scene
is identified and marked, they are tossed into a cardboard container
at the side of the editor. This procedure is continued until each
scene, photography, sound effects, and voice, have been properly
identified and numbered.

The next step is to take the box of identified reels and place each
reel on the correspondingly numbered peg on the wall, as seen in Fig.
7. After each scene has been identified and hung on its respective

Dec., 1943]

PHOTOGRAPHIC EMBELLISHMENTS

483

peg, the editor may rearrange the sequences or individual scenes.
In other words, with each reel properly identified and numbered,
the editor can see his whole show scene by scene, sequence by se-
quence.

The next step is to splice these scenes together in sequence, begin-
ning with reel one, until there are approximately 390 ft on a reel.
After this is done the reels of film are sent to the laboratory and a

FIG. 7. Identified scenes placed on the wall rack.

black-and-white work-print is made from them. The same pro-
cedure is followed with the synchronized sound-track and sound-
effects track. When this material is returned from the laboratory,
the editor has the original photography, sound-effects track, syn-
chronized voice track, and work-prints of each.

As mentioned above, due to the lack of universal edge-numbering
a technique was developed that enables the editor to synchronize
the work-print with the original photography. This is done by
putting the strips of film into a synchronizing machine and then
nicking a frame, using a small built-in nicking device, in each strip

484

L. SHERWOOD

[J. S. M. P. E.

synchronously, as shown in Fig. 8. This notch then acts as a guide
for synchronizing the original material with the work-print, after the
work-print has been completely edited. In other words, this notch
acts as a guide in the final process of matching the original photog-
raphy with the work-print.

Upon completion of this operation, the original photography,

FIG. 8. Notching device on synchronizing machine.

original sound-effects track, and original synchronous voice track are
put away, and the editing of the film is begun, working entirely with
the work-prints.

The procedure is to edit the picture in the normal manner, with
one exception. One foot of film is cut off at the end of the scene and
1 ft at the beginning of the succeeding scene between which it is
desired to produce an effect. In so doing, there will be a surplus
of 1 ft of original film at the end of one scene and the beginning of the
succeeding scene, which allows an overlap of 2 ft in the original.

Dec., 1943]

PHOTOGRAPHIC EMBELLISHMENTS

485

Simultaneously, the sound-effects and voice tracks are edited into the
picture. After the film is so edited and all sound-tracks matched,
this work-print is utilized as a guide for the narrator, and further
as a guide for the music track. The music track, sound-effects
track, and the narrative track are then re-recorded and balanced to
produce the final sound-track that is to be printed to the picture.
It is difficult for me to refrain at this time from discussing the

FIG. 9. Leaders showing punched synchronous frames.

merits of the direct positive system, or the reversal system as com-
pared with the negative positive system ; and also variable area with
variable density sound-tracks. To save myself involvement, I will
leave that to my engineering friends. Suffice it to say that we have
found the former in both cases to be much more satisfactory.

Now, that the work-print is edited, the music track re-recorded,
the narrative track recorded, the sound effects all re-recorded and
combined into one film, we are ready to enter into the final stages of
editing. These final stages consist of matching the original photog-
raphy to the work-print, and at the same time preparing the travel-
ling mats which contain the effects — and therein lies a tale.

486

L. SHERWOOD

[J. S. M. p. E.

It is somewhat difficult to explain the method of procedure, yet in
reality it is extremely simple. The original photography will be
edited into two strips of film, which for convenience we will call A
and B. The mats will also be edited into two strips of film, coinciding
with the A and B photography. In short, there is a strip of A photog-
raphy and a strip of B photography, and a strip of A mat and a
strip of B mat, shown in Fig. 9. We then make up leaders, place

FIG. 10. Re-recorded track showing "sync" hole.

them in a synchronizing machine with the work-print and punch a
particular, synchronous frame in each strip.

There is one exception, and that is the re-recorded track which is
marked with the cross and the "sync" hole placed 25 frames down.
This is done so that the final print will carry the sound 25 frames
ahead. This will compensate for the distance between the projec-
tion light source and the sound light source. The leader is necessary
for threading into the printer and in checking synchronization, Fig. 10.

The film is wound down to the first scene of the work-print; and to
the leader marked "photography A" splice the first scene in exact

Dec., 1943]

PHOTOGRAPHIC EMBELLISHMENTS

487

synchronization with the work-print. The synchronization is deter-
mined by the notches previously placed on the sides of the film, when
working with film that is not edge-numbered.

To the leader of mat A is spliced a strip of transparent film, which
in the printing process will allow the light to pass through this mat
and print the scene on photography A on the raw stock. On photog-
raphy B there is spliced the normal leader film, which in the case

FIG. 11. Reading from top to bottom: sound-track, work-print, original
photography A, original photography B, mat A, and mat B.

of exposed film is yellow in color. On mat B there is spliced a strip
of black film. This black film is produced merely by running the
exposed film through normal processing. The result is that the
yellow leader on photography B will be blacked out. The film is then
rolled down to the second scene and matched to the work-print by
the same method as in matching photography A .

There is an overlap of 2 ft in photgraphy A and B. Now, to in-
sert a mat : these mats can be made up in any form the imagination
can develop — lap dissolves, straight vertical wipes, horizontal wipes,

488

L. SHERWOOD

[j. S. M. P. E.

circle wipes, etc. For clarity, let us assume that a straight left to
right vertical wipe, or effect, is wanted between the first and second
scenes. This straight wipe consists of two pieces of film, one nega-
tive and the other positive. These mats are matched so that wherein
A has a clear portion of film, B will have a black portion. The mak-

FIG. 12. Printer.

ing of these mats is a simple process and we will not take the time here
to discuss the manner in which they are made (Fig. 11).

Now, to proceed from photography A to photography B: splice
the part of the effect film with the greatest clear portion to the clear
film of mat A ; then, the positive mat with the greatest black portion
is spliced to the black portion of mat B. Each and every effect is
produced in this manner. In other words, wherever it is desired to
produce an effect, the photography is moved from B to A, or A to B,

Dec., 1943] PHOTOGRAPHIC EMBELLISHMENTS 489

whichever the case may be, producing an overlap of film. Then
an effect is inserted at that juncture in order to be printed.

In the printing process, Fig. 12, photography A and mat A are run
synchronously and the light of the printer is allowed to pass through
mat A and through photography A , exposing the picture on the raw
stock. In other words, wherever mat A is clear and there is a picture
on photography A, that picture will be transferred to the raw stock.
When a mat presents itself to the printing light, it allows exposure to
be made on the raw stock in direct proportion to the amount of clear
film characteristic to that particular mat — only that portion of
photography A at that particular juncture is transferred to the raw
stock.

Then the raw stock is again exposed in the printer, utilizing pho-
tography B and mat B. The process is exactly the same as that ex-
plained for photography A and mat A . The result on the final print
is the desired effect, creating a transition from one scene to another.

At this time, we should perhaps discuss the use of these so-called
photographic embellishments. We choose to call these effects
"photographic embellishments" simply because in most instances
any other types of effects are not, due to inadequacy of equipment,
plausible in 16-mm industrial and educational films. We have not
found it necessary in the industrial field to utilize many of the photo-
graphic embellishments used by theatrical producers, such as in-
volved or fancy montage effects, processed backgrounds, etc. An in-
dustrial and educational film might be differentiated from a dramatic
or theatrical film in that, in most instances, the former is a picture of
processes rather than of impressions. True, many industrial and
educational films must create an impression; therefore it would be
clearer to state it more simply and say that an industrial and educa-
tional film concerns itself with specific and detailed information rather
than emotional and philosophical impressions. Consequently, we
choose to call lap dissolves, various types of wipes and trick effects,
etc., simply effects. We do not like to refer to these effects as em-
bellishments for they are rather a necessity — and, if you please, an
economic one.

In fact, it is possible to conceive that effects of the nature under dis-
cussion can within themselves be potential educational factors. One
illustration: it is a matter of record that by habit the human eye
travels to the left when presented with a screened object. Suppose
it becomes necessary to direct the attention of the audience to the

490 L. SHERWOOD [j. s. M. p. E.

right side to derive the maximum educational value from the scene.
We merely introduce the picture with a vertical right to left wipe.
The action of the effect draws the attention to the right side of the
frame, thereby directing the attention of the audience, and ob-
viously minimizing the normal reaction of left to right visualization.
In so doing, perception is improved and memory enhanced.

It is practically impossible to use too many effects, if they are used
intelligently and judiciously. An effect may be compared to punctu-
ation in writing prose or poetry. It is possible to use a great deal of
punctuation in writing an article or essay, but that punctuation
becomes ineffective the moment it becomes excessive. The same idea
may be expressed with regard to the utilization of effects in editing
an industrial motion picture. Industrial and educational motion
pictures by their very content need such photographic effects much
more than a theatrical or emotional type of picture, simply because
most industrial or educational pictures do not, by their very nature,
fall into connected and related sequences.

There are many things, due to the time element, which must of
necessity be left out, or perhaps left to the imagination of the audi-
ence. To illustrate : if we want to show the manner in which a dust
cap is put on the valve of a tire (which at this particular time we
would like to look at), it is not necessary to show each step of the
process of how the dust cap is screwed down on the tube, but we can
take the cap and start the process, then through the use of a lap dis-
solve or some significant effect, eliminate the time element and make
a scene that is short, yet clear and concise in every detail.

Yes, effects may be likened to punctuation. What can be said of
one can be said of the other. If punctuation in the sentence is ob-
vious to the reader, it ceases to be good punctuation. It loses the
power that should belong to it. The same thing can be said of effects.
Any effect that is obvious is not a good effect, because the moment
the audience becomes conscious of the transition created by an effect,
that effect begins to detract from the intent of the story and from
the intent of the effect. Therefore, in saying that it is almost im-
possible to use too many effects, it is to be thoroughly understood that
this statement does not hold true unless such effects are used judi-
ciously.

Now, there are various methods of using effects in order that
they do not become obvious. As an illustration, suppose a picture
of two types of files, side by side on a bench, is wanted. It is desired

Dec., 1943] PHOTOGRAPHIC EMBELLISHMENTS 491

to explain the difference between a single-cut bastard cut file and a
double-cut bastard cut file. Upon examining such a file, it is evident
that the teeth of the file are microscopic. First, a scene is taken,
perhaps a medium close-up, as an establishing shot in order that the
audience may know at what they are looking. Now, it is necessary
to go farther than that and bring the audience to a microscopic view-
point. To use a straight vertical wipe at this place, or a lap dissolve,
or a horizontal lift wipe, or any other type that the imagination may
conceive, would be in poor taste and would immediately confuse
the audience.

However, if one uses a circle wipe and in shooting the picture has
a hand with a pencil come into the establishing shot, then, with the
use of the circle wipe, have the pencil come into the microscopic close-
up in the same manner, the circle wipe will create in the minds of the
audience the feeling that they are seeing these files through a micro-
scope. This is one example of judicious use of a particular effect.

As another example, we have a train sequence or montage in which
it is desired to create the idea of travelling over some distance. A
straight vertical wipe between each shot of the sequence or montage,
travelling in the same direction as the action on the screen, will
create in the minds of the audience the idea of continuous travel.
Now, if this vertical wipe should be edited into the picture in such
manner that it is contrary or against the movement, the audience is
again confused. While if the effect is placed in the picture so that
it moves with the action, the audience at no time will become con-
scious of the fact that an effect has been used.

Another advantage of effects is the elimination of excessive footage.
Those who have had experience in the industrial or educational field
realize that this is one of the greatest problems confronting the
educational and industrial motion picture producer; therefore, a few
examples of how an effect may be employed to reduce footage will be
discussed.

Suppose we have one scene of a close-up of an entrance to a build-
ing and in the shooting of the picture want the close-up of the en-
trance to be followed by a low-angle shot to the top of the building.
If the building is of any size, it would take from 20 to 25 ft of film to
execute this upward "pan." The same effect can be created by in-
serting a horizontal lift wipe between these two pans. The audience
will not be conscious that an effect has been used, and it is possible
to cut down 12 or 13 ft of film in this one sequence.

492 L. SHERWOOD [J. s. M. P. E.

As another example, and there are hundreds of such, let us as-
sume that we are shooting an oil drill operation and want a low
camera angle of the "Kelly" being hoisted into the tower and then
lowered with the pipe into the hole. If such an operation is ob-
served, it is realized some little time elapses from the time the Kelly
is pulled to the top of the tower until it lowers the pipe into the hole.
The camera shows the cable and Kelly drawing the pipe into the
tower, then a lift wipe can be used to follow it up, and the Kelly can
immediately lower the pipe into the hole. This would realize a
saving of 20 to 25 ft of film.

The question no doubt immediately arises, "Why not use a lap
dissolve?" The answer is simple. Both shots are taken from the
same angle. A lap dissolve inserted at this juncture would create
an image displacement, because it would be physically impossible
to pan up with the camera, then pan down and utilize this extra
footage in a lap dissolve without losing registration or having a
change of camera position, though it might be very slight.

A generality that may be of value concerns itself with where and
when to use effects. We have found it good general policy to use a
wipe of one sort or another — most of the time a conservative left to
right wipe — to introduce more or less unrelated sequences, and then
within the sequence use lap dissolves to show the passage of time or
to eliminate footage. Of course, this is a general statement and can
not be expected to meet all requirements.

I wish that I were in a position today to give you some statistical
data regarding the use of certain types of effects. There are a num-
ber of questions that arise. First, should you ever in an industrial
or educational motion picture use a right to left wipe? Should you
ever use a split scene? What portion of the picture is lost by the
use of a particular effect? What is the percentage of confusion or
lack of confusion between a straight cut picture and one using effects?

I hope by this time next year to be in position to offer you such
statistical material or data. I have been invited to collaborate in
research, and am now in the process of working with Dr. W. I.
Gooch, Director of Education for the Boeing Airplane Plant, and Mr.
Russell Mosser, in charge of visual educational training of the Boe-
ing Company.

We hope by these studies mentioned to clarify a great many prob-
lems regarding industrial and educational films. We have the not
too vain hope that we will be able to clarify at least a few of the prob-

Dec., 1943] PHOTOGRAPHIC EMBELLISHMENTS 493

lems involved regarding industrial and educational motion pictures.

It is the hope that soon even greater strides will be made by the
engineers of the industry in developing better and more efficient
equipment.

Sixteen millimeter is a growing and progressive industry — it is
progress. I think that it was not said — but should have been — in
McGuffey's first reader that "Some individuals may retard progress,
but no group of individuals can ever stop it."

RECENT DEVELOPMENTS IN SOUND CONTROL FOR
THE LEGITIMATE THEATER AND THE OPERA*

HAROLD BURRIS-MEYER**

Summary. — A series of experiments involving the control of reverberation and
spectrum as applied to both music and speech, has brought to a conclusion the research
project directed toward the complete control of the auditory component of legitimate or
operatic production.

Before this Society, at the Rochester meeting last year, I had the
privilege of demonstrating Synthea, the acoustic envelope designed
for concert use. During that same season and the one just past, the
research enterprise which fathered Synthea tested in production a
number of other gadgets »and techniques designed to complete our
job of subjecting all sound in the theater to electronic control.
If you really want to, you can now make the audience hear just what
you desire, the way you want it. The artist has complete control of
the auditory component of the "show." It is gratifying to have ac-
complished this, even though priorities and artistic conservatism
will delay the full exploitation of electronic means of sound control.
This technique will achieve its maximum usefulness only when the
motion picture has facilities to employ it and make it an integral part
of our dominant art form.

The control of reverberation has been successfully undertaken in
motion pictures and radio. The devices involved have included the
echo chamber, vibrational transmission along springs, and various
means of recording and near-instantaneous playback. The problem
in the legitimate theater is complicated by several conditions not
encountered in radio or motion pictures: first, the legitimate the-
ater, or opera house, usually has longer reverberation at most frequen-
cies than the average motion picture theater, or the room in which the
radio receiver is located; second, the difference between the sound
intensity of the show and the background audience noise level is
generally less than in the case of motion pictures; third, the audience

* Presented at the 1942 Spring Meeting at Hollywood.
** Stevens Institute of Technology, Hoboken, N. J.

494

DEVELOPMENTS IN SOUND CONTROL 495

at a legitimate, or operatic production, conventionally demands much
greater subtlety and flexibility in the auditory component of the show
than is demanded of any other medium.

Devices for control of reverberation in the legitimate theater and
the opera must, therefore, possess ultimate flexibility. They must
be able to reproduce reverberant conditions within the acoustic limi-
tations of the theater, including echoes found in structures and in na-
ture, and must be susceptible of producing arbitrary, suggestive, or
exaggerated phenomena in conformity with artistic demands, which
do not necessarily involve imitating nature.

The only devices capable of filling these requirements employ the
principle of recording and multiple playback. In fact, for the satis-
factory interpretation of music, Leopold Stokowski has suggested
that it is probably worth the effort to divide the frequency spectrum
into a number of zones and have independent control of the apparent
decay time in each zone. Such a technique makes possible the per-
formance of any piece in the manner intended by the composer ir-
respective of the reverberation of the place in which it is performed,
and will give added scope for new interpretations.

The first episode employed to study the theatrical use of reverbera-
tion control was Widor's Toccata in F, to which we added enough
reverberation to approximate that in the Church of St. Sulpice. The
experiment was welcomed with considerable enthusiasm by all but a
few members of the audience that included a number of eminent
musicians. Two members, who had heard the Toccata played in
St. Sulpice, declared we had reproduced exactly the acoustical condi-
tions obtaining there. I doubt we did as well as that. Audience
enthusiasm may be attributed to these factors : first, the Toccata in F
is in itself a most effective showpiece, and it was staged for a maximum
effectiveness within the limitations of the theater; second, its per-
formance by the organist was excellent; and, third, the piece was
played at peak levels high enough to make almost anything exciting.
Those of you who heard the same piece played by stereophonic record-
ing at the Eastman Theater last year, or at Carnegie Hall, or at Pan-
tages the year before, can easily realize what controlled reverberation
could do for it.

Reverberation in our test was accomplished by recording on steel
tape by the device developed by S. K. Wolf. The reverberation ma-
chine was so arranged that the first playback occurred l/8 of a sec after
recording of the original sound, and 3 sec passed before the last play-

496 H. BURRIS-MEYER [j. s. M. P. E.

back dropped below audibility. The first playback was 6 db below
original level; the last started 15 db below. There were 9 inter-
mediate pick-ups, adjusted in point of time to conform to acoustic
conditions of the theater. The first playback had to be delayed to
avoid feedback until the level of the normal reverberant sound in
the theater had dropped 6 db.

The Toccata was originally played on the Paramount Theater
studio organ, recorded on a vertically cut disk, and played back over
52 speakers located in the house and stage. The reverberation play-
back was through a separate set of speakers to contrast in direction
with the original sound. The quality of the recording was sufficient
to deceive the audience, who believed a real organ was being played in
the theater. The fact that the piece as played had almost no pauses
made it sometimes difficult to perceive the dying away of single notes.
Applause followed so soon after the final chord that its reverberation
was never perceptible for more than the first second. Because of
these conditions, it may be argued that reverberation can be even
more effectively added to some of the compositions of Bach.

The same apparatus was employed in the Church Scene from
Faust in which Margarita's efforts to pray are stifled by the presence
of the voice of Mephistopheles. The production scheme for this
scene was worked out by Dr. Herbert Graf who had long been anxious
to employ reverberation control in it and to use the voice of Mephis-
topheles in auditory perspective rather than to have him appear on the
stage. We first experimented with the technique in the Metropoli-
tan Opera House. Later, the test scene was produced at Stevens.
As we staged it, the song of Margarita coming directly from the
singer, the voice of Mephistopheles coming from speakers located in
various places at various times, the organ accompaniment coming
from speakers backstage, and the orchestral accompaniment, were
picked up and played back via the reverberation apparatus. The
added brilliance and churchlike quality were particularly noticeable
in the first five measures of Margarita's song, which is unaccom-
panied.

The experiment with Faust was so successful as to make us confi-
dent that the technique involved may be employed to good advan-
tage in opera, in that it serves to establish locale, create mood, and
generally carry out the intention of the composer more faithfully
than any other means so far attempted.

By far our most interesting set of problems has been concerned with

Dec., 1943] DEVELOPMENTS IN SOUND CONTROL 497

the control of sound that is used to convey intelligence, as in the case
of human speech or song.

Back in 1934 we set out to make the Ghost in Hamlet sound like a
ghost. We built a voice which was appropriately sepulchral and
dubbed it onto an ectoplasmic figure. It created quite an impression.
The technique of making the voice consisted in suppressing some of
the voice frequencies while emphasizing others. It was not long be-
fore the same idea, adapted to radio as a sort of juke-box voice, be-
came part of the standard radio bag of tricks.

It is all very well to control speech by removing some parts and
amplifying others, but no matter how cleverly a job is done, one is
still hindered by the limitations of the human voice itself. To avoid
these limitations one must completely remake the voice. Everyone
of us is familiar with, and many have used, the various devices for
making speech out of other sounds — the pitch pipe on a rubber tube,
the Sonovox, the Vocoder, Professor F. A. Firestone's substitute lar-
ynx, and the Voder. They have their uses. Most have many
limitations, and none carries conviction unless the spectrum of the
sound of which speech is to be made is nearly as wide as the speech
spectrum, or unless a visual cue makes the sense of the speech per-
fectly apparent. These limitations will be illustrated presently.

Despite limitations, there are few elements in dramatic technique
that are more intriguing than those involving speech or song by ani-
mals or things not endowed with such powers. Shakespeare has
Alonso in The Tempest say :

Methought the billows spoke, and told me of it;

and the thunder,

That deep and dreadful organ-pipe, pronounc'd
The name of Prosper.

We tried making speech out of wind and thunder last year. It was
not so bad when we could get better than 100 db out of the thunder,
but it is awful without adequate dynamic range.

We did a little better in an experiment, worked out by Margaret
Webster, to see whether the Witches in Macbeth could be made into
twentieth century demons. These are visible only to Macbeth but
cast visible shadows as they moved around the fire. The voices
could not carry the show without adequate staging of the visual ele-
ments. The voices of three actresses were so rebuilt that their
owners would never know them. One was made higher than the

498 H. BURRIS-MEYER [j. s. M. p. E.

human voice can go, another was given a quality which was a cross
between a rock-crusher and a whiskey baritone, and the third was
transformed into a basso. For the production, the dialog was played
against a background of the scherzo of the Prokofieff's Concerto in
D Major for violin and orchestra. (Here a recording of the Witches
without the background music was played.)

In Eugene O'Neill's Lazarus Laughed, an attempt was made to give
the laughter the muscial quality and dynamic range prescribed for it.
The laughter serves in fact as a musical accompaniment to the play
and, in addition, motivates action and carries the final scene. We
modulated a chord, played on an organ, with human laughter and
accomplished variation by the relative amounts of voice and music
used, and by the dynamics of the chord.

Inquiry elicited comments that the laughter was appreciated for its
novelty, and that it fitted into the production so well as to be ac-
cepted without question. I am inclined to feel that we scratched the
surface only of what is possible with the play, particularly in the last
scene which we used. Scoring all sound in the scene according to a
musical pattern, as we did for The Emperor Jones and for Cyrano de
Bergerac in the program of stereophonic recordings, and giving the
laughter a varied instrumentation would, I am certain, enhance the
effectiveness of the play beyond what has been possible heretofore.
Here is the laughter which is a continuous background to part of the
scene — sometimes barely audible, sometimes dominant. (A record-
ing was played at this point.)

When Shakespeare put an ass's head on Bottom in A Midsummer
Night's Dream, he did not have any but mechanical control of Bot-
tom's voice. We thought it would be worth while to see if Bottom
could speak with the voice of an ass while wearing the ass's head, and
with his own voice the rest of the time. Significant characteristics of
an ass's bray seem to be: (1) he uses only vowels; (2) his fundamen-
tal frequency range is greater than that of a human voice — he pro-
duces his loudest sounds at the high and low ends of that range with
little power in the middle; (3) he uses his whole range all the time.
Once the Vocoder is set up to produce such a sound, almost anyone
talking into it sounds like an ass. You will notice that the ass's
voice has a much wider pitch range than the human voice and that
enough of the human voice is mixed with that of the ass so that Bot-
tom can at least be recognized. The dubbing was accomplished by
reproducing the voice from speakers upstage of the actor, and varying

Dec., 1943] DEVELOPMENTS IN SOUND CONTROL 499

the output between speakers as the actor moved about the stage.
(A recording demonstrating the voice of Bottom was played.)

Since these voices were made for a special theater use, it is not likely
that they fulfilled all the requisities for voices similarly conceived but
designed for motion picture use. I think they may illustrate, how-
ever, what is likely to be in store for us. So, tomorrow, if your alarm
clock bell wishes you a cheery good morning, do not rush to the near-
est psychiatrist. It may only be the sound department run amok
again.

Ed. Note: This paper contains extensive quotations, not otherwise noted, from
the author's "Theatrical Uses of the Remade Voice, Subsonics and Reverberation
Control," published in The Journal of the Acoustical Society, 13, No. 1 (July, 1941),
p. 16.

SOUND CONTROL IN THE THEATER COMES OF AGE*
HAROLD BURRIS-MEYER**

Summary. — Some of the implications of the control of the auditory components
of a "show" are noted, especially its application to the exhibition of motion pictures.

It has been my privilege to report to this Society from time to time
various steps toward the control of the auditory component of the
"show." That control is now complete. The purpose of this paper is
to note some of the implications of its application to the motion pic-
ture.

There is no need to sell, on artistic or technical grounds, the de-
sirability of exercising complete control over everything the audience
hears. Good performances without number demand more scope in
the control of sound than is possible with conventional apparatus.
Apparatus and techniques exist to satisfy these demands. Box office
figures confirm the fact that the more flexible the artistic medium, the
more the showman prospers. There is danger, however, that when
we start to remake the motion picture technically and as an art form
after the war, we shall not go far enough in the first step; that we
shall limit future developments with stopgap apparatus, thereby miss-
ing the greatest opportunity ever to present itself to the industry.

We realize how changed the motion picture would be now if the
war had not come along. Many of us know developments made as a
part of the war effort which will be applicable to the motion picture
when military classification can be removed. With technological
progress almost completely stymied, it behooves us to crystallize and
agree on our concept of what the post-war motion picture will be like,
and to define its objectives to the end that we shall be able to achieve
them without a period of technological chaos when the war is over.

Moreover, it is extremely important that we be ready when the
time comes. The motion picture is the most important popular art
form in the world, and the American motion picture is its most popu-

* Presented at the 1942 Fall Meeting at New York.
** Stevens Institute of Technology, Hoboken, N. J.

500

SOUND CONTROL IN THE THEATER 501

lar version. It has had a tremendous effect upon the feelings, habits,
hopes, desires and fears of the common man the world over. The
impact of the American motion picture when it returns to inter-
national circulation will be very great. Its power for good or evil is
hard to evaluate. If we make it flexible enough to permit the Ameri-
can artist to do a superlative job, we shall at least have the preferred
path to the emotions of all peoples, for many of whom the best ele-
ments of the American way of life constitute an ideal.

To make the motion picture what it can and will be, we must en-
hance the scope of sound control. We have a long way to go. When
sound came to the movies, it took time for the idiom to jell, but pres-
ently a reasonable integration between the picture, the spoken word
and instrumental music was achieved. As matters stand now, sound
is still definitely subordinated to the picture. Song arid instrumental
music are reasonably well reproduced; speech comes over with a
tolerable percentage of articulation; effect and background sounds
are still, I regret to say, but slight variants of the sound of coal going
down a chute. When you listen to the sound-track without the pic-
ture, you are well aware of how woefully inadequate it is. This is a
deplorable condition. Of the senses that we bring to the theater
through which the artist reaches our emotions, the sense of hearing is
measurably more effective as a path to the emotions than is vision.

You can do a lot with sound. You can use it as a direct emotional
stimulus; you can induce a physiological basis for the generation of
emotion. With sound, you can control metabolism; you can in-
crease or decrease muscular energy; you can increase respiration;
you can increase or decrease pulse rate ; you can control the threshold
of sensory perception; you can reduce, delay, allay or increase fa-
tigue. The techniques for accomplishing all these ends exist. It is
susceptible of use as a part of an artistic idiom. To the extent per-
mitted by technical limitations, it has been an element in the show-
man's art since there first were "shows." It still awaits full, con-
scious exploitation.

Moreover, not only can you do almost anything with sound,
but your audience can not escape it. You can shut your eyes if you
will, but the sound comes out to get you. I submit that in its prog-
ress the art of the motion picture has overlooked or, at best, only
vaguely glimpsed its most powerful and, by the same token, its most
subtle instrument.

Obviously, if you can make an earnest endeavor to get the most out

502 H. BURRIS-MEYER [j. s. M. p. E.

of the sound, you have to get it under control and keep it so. This
involves :

(1) Control of the intensity of the sound. The dynamic range must be from
several db below theater ambient noise level (in a well-designed theater, this level
will stay substantially below 40 db), to at least 120 db, which is a perfectly toler-
able intensity with tremendous effectiveness when used with discretion. Such a
dynamic range must not be accompanied by harmonic distortion at the peaks.
It must be possible to record and reproduce sounds with steep wave fronts as
found in explosions or in some compositions of Moussorgsky.

(2) Control of the spectrum, which involves the ability to get any auditory
signal, including frequencies above and below audible range, on the track and
back off it again, to all members of the audience. It means remaking, otherwise
electronically reprocessing or synthesizing any sound to give it any predetermined
spectrum. It means a theater in which the sound is so distributed that all the
frequencies on the track reach everyone in the house at substantially the appro-
priate levels. Only with such control of spectrum will the drum in Emperor Jones
have maximum effectiveness, or cause the opera goer to prefer the celluloid to the
stage production.

(5) Control of reverberation. This means not only electronically controlled
over-all decay time, but control of the shape of the decay curve in at least three
separate frequency zones. It means theaters with uniform sound decay patterns,
with all variations therefrom carried on the film. Then an organ record may
sound like a cathedral organ, echoes may be realistic, and a scene in a tent may
sound like a scene in a tent.

(4) Control of the apparent direction ot the sound. This means having the
sound come from any point in a sphere surrounding the audience — from the pro-
jection booth, from below the stage, from over the proscenium, from the side wall,
or from no place, or from an apparently moving source, i. e., starting in one loca-
tion and ending in another. It means freeing the sound from the spatial limits of
the screen so that the Angels' Chorus can be heard from above, or the laughter of
Lazarus can envelop the audience.

(5) Control of the apparent distance from which the sound comes. This sug-
gests that the sound must appear to originate from any point or area in a sphere of
any size surrounding the audience. It must be able to move along a straight or
curved line from any point in any sphere to any point in any other sphere; for
example, a mile behind the projection booth to a point within the ear canal of each
member of the audience. The control of apparent distance involves, of course,
control of direction and control of spectrum.

This is a large order. Yet every element of it has been employed in
the theater before audiences who bought their seats to see a "show,"
most of whom were unaware of the nature or extent of any sound con-
trol to be involved, and many of whom do not know to this day that
anything they heard had an electronic origin. Moreover, the ap-
paratus now exists by which all of these ends may be accomplished
in the motion picture, and there is at least enough technique available
to keep the artist from bogging down when first he tries his new wings.

Dec., 1943] SOUND CONTROL IN THE THEATER 503

To accomplish the flexibility of sound control which has been out-
lined here, we must have, first, new apparatus, the nature of which
you already know; second, a considerable revision of production tech-
nique; and third, new theaters.

The making of the multichannel record requires that the script
writer should know what his enhanced medium will do. The stereo-
phonic recordings already made, and the legitimate and operatic pro-
ductions which have used the Stevens sound control technique, will
serve only to point the way, for they have lacked either the visual
component or the ubiquitousness which the motion picture provides.
The artistic scope of the motion picture is, for the first time in history,
literally bounded only by the limits of the artist's imagination.

The multichannel record will demand a revision of current stand-
ard practice from script to cutting room. Music, dialog, and other
sounds will have to be planned with a view to where they come from,
how they move, and what their reverberant characteristics will be.
The sound score will have to be more elaborate than that currently
employed in the animated cartoon, as those who have made stereo-
phonic records can testify. The work of making the final sound-
track from the original will be increased and for a while, until new
techniques are mastered, those who make the sound-track will have
quite a job keeping up with the artist's fancy.

Then we need new theaters. Theater building has languished for a
decade, during which we have almost learned how to build a theater.
Many existing theaters are ready for the wreckers; many more are
economic liabilities. They will have to be replaced. And though
obviously many will be built for productions other than motion pic-
tures, none should be so built that they can not exhibit motion pictures
in a manner which is technically simple, artistically satisfactory, and
financially sound. The English are already collecting theater plans
and specifications against the day when they rebuild after the blitz.

In planning for the control of sound in the theater that is to be, I
submit the following fundamental considerations :

(7) Two elements in the manner in which sound is heard determines its ac-
ceptability :

(a) percentage of definition, a subjectively determined standard embracing per-
centage of articulation and blending, and taking cognizance of the direction and
efficiency of sound sources;

(6) a vibrant characteristic, embracing the cyclic pattern common to the decay
curve and the vibrato, whose characteristics are to be determined by a subjective
appraisal of the vibrato rate and decay curve form.

504 H. BURRIS-MEYER

(2) There is an optimum duration for decay of speech which is valid, irrespec-
tive of the size of the theater. The decay time for sound must be the same irre-
spective of the number of people in the theater.

As to music, decay time has been used consciously or unconsciously
by the composer as a musical device. It is therefore impossible to
make one decay time do for all music. In a theater planned to pro-
vide optimum decay time for speech, electronic control of all other
sound can be simple and effective, and chamber music, organ music,
and opera may sound as the composer intended, irrespective of the
size of the theater or the audience.

There will have to be, of course, provision for speaker placement
to provide by direct transmission, or reflection for the directional and
spatial characteristics the sound must have. You can not make such
provision after a theater is built. It must be designed from the start
as a part of the acoustic planning, and it will have to be sufficiently
uniform and simple to make one type of print satisfactory wherever
it is shown.

The objectives I have set are not easy of attainment, to be sure, but
they carry the promise of dominance of the world market, and the
greatest influence on the most people that any art form has ever had.
That is a tremendous responsibility. We shall shirk it if we are satis-
fied with technological half -measures.

RECENT LABORATORY STUDIES OF OPTICAL
REDUCTION PRINTING*

R. O. DREW AND L. T. SACHTLEBEN**

Summary. — This paper reports recent laboratory work which has resulted in
marked improvements over previous 16 -mm reduction print quality. Improvements
in image quality accrue from exposure oj the print with ultraviolet light and from the
use of reflection reducing coatings on the lens surfaces, while speed variations are re-
duced by increasing printer speed up to as much as twice normal film speed. These
improvements involve only relatively simple changes in commercial reduction printers.

The reduction sound printer1 was developed because it promised
to be the best means of making 16-mm sound-track prints from
original 35-mm sound negatives. The earliest method of making
such prints involved re-recording, and the unsatisfactory results ob-
tained by that method led to efforts to make the prints by optical
reduction. The prints so made showed such marked improvement
over the product obtained by re-recording2 that the reduction printer
was developed into a commercial machine.

The loss of quality in re-recording took place largely in recording
the 16-mm sound negative. Efforts to compensate these losses by
equalization led to an intolerable distortion. This was later found
due to a rectification component originating in the failure of the 16-
mm film to resolve the higher frequencies impressed upon it. This
failure to resolve the higher frequencies had a double aspect: (a)
the wavelengths at any given frequency were only 40 per cent as
great on 16-mm film as on 35-mm film, and the loss of resolution due
to irradiation in the emulsion was thus greatly aggravated; and (b)
the recordings were made with the same slit widths used in 35-mm
recording optical systems with a resulting increase of 150 per cent in
the ratio of slit width to wavelength at any given frequency. The
reduction printer afforded greatly improved 16-mm prints, as well as
a more direct method of making them from 35-mm negatives that
involved less and simpler equipment.

* Presented at the 1942 Fall Meeting at New York.
** RCA Victor Division of Radio Corporation of America, Indianapolis, Ind.

505

506

R. O. DREW AND L. T. SACHTLEBEN [J. s. M. p. E.

Since the development of the first successful optical reduction
printer, advances in 35-mm sound-recording methods and equipment
have been great. Notable among these advances have been exposure
of the sound negative and print with ultraviolet light,3 and the
introduction of the fine-grain emulsion as a sound-recording medium.
Parallel advances have been made in the special technique of record-

FIG. 1. Photomicrograph of 7000-cycle track printed
on Eastman 5302 stock, using white light uncoated
lenses and white light exposure. Print Density 1.0;
Print Gamma 2.0.

FIG. 2. Photomicrograph of 7000-cycle track printed
on Eastman 5301 stock, using white light coated lenses
and white light exposure. Print Density 1.2; Print
Gamma 2.0.

FIG. 3. Photomicrograph of 7000-cycle track printed
on Eastman 5301 stock, using white light coated lenses
and ultraviolet exposure. Print Density 1.2; Print
Gamma 2.0.

ing directly on the slower moving 16-mm film.4 These have been
successful to the point where 16-mm prints made from the best ori-
ginal 16-mm sound negatives show improved quality over 16-mm
prints made from 35-mm original negatives on an unimproved optical
reduction printer. For various reasons it has remained until the
present time to show the extent to which the product of the reduction
printer may be improved by adoption of means made available since
these printers were built.

Dec., 1943] OPTICAL REDUCTION PRINTING 507

In studying the possibilities of improving reduction prints, the
following desirable advances were made the objective:

(1) Increased density in the black areas of the print.

(2) Reduced fog density in the clear areas of the print.
(5) Extended frequency range and reduced distortion.

(4) Reduced image grain.

(5) Reduced "wows" in the prints.

Proved experience in the 35-mm sound-recording field suggested
the redesign of the reduction printing optical system for ultraviolet
light, and the ultraviolet exposure of the reduction print, as a most
promising step in the printer's improvement — and this step was
taken. The presence of the large number of glass-to-air surfaces,
characteristic of the optical trains of reduction printers, suggested
that the newly developed lens coating process should be employed
to reduce the stray light resulting from reflections5 at those surfaces.
This was also tried. Prints were made on the new fine-grain emul-
sions with both white and ultraviolet light to learn what improve-
ments might result from the use of such emulsions. Finally an
effort was made to learn if the wows introduced into the reduction
prints by the printer itself could be reduced by an increase in the
speed of the printer.

The laboratory studies made along these lines, and here reported,
indicate that reduction printers can be greatly improved in all of
the above tabulated respects.

OPTICAL IMPROVEMENTS

An optical reduction printer was obtained from a commercial
laboratory. It was put into optimum adjustment, and a series of
prints were made for each of the conditions tabulated in Table I
below. Thirty-five-millimeter ultraviolet exposed speech and music

TABLE I

Printing Conditions

Condition

Type of Optics

Lens
Surface
Condition

Quality of
Light Used

Eastman
Emulsion
No.

Gamma

White light

Uncoated

White

5302

White light

Coated

White

5301

White light

Coated

Ultraviolet

5301

Ultraviolet

Coated

Ultraviolet

5301

White light

Coated

White

5302

2.5

Ultraviolet

Coated

Ultraviolet

5302

2.5

508

R. O. DREW AND L. T. SACHTLEBEN [J. S. M. p. E.

negatives were printed for listening tests to learn which were the
best negative and print densities to use. Frequency prints were
made under the conditions so determined, and their response meas-
ured.

The speech and music prints made under conditions 2 through 6
were carefully listened to by a group of three observers, who con-

FIG. 4. Photomicrograph of 7000-cycle track printed
on Eastman 5301 stock, using ultraviolet coated lenses
and ultraviolet exposure. Print Density 1.2; Print
Gamma 2.0.

FIG. 5. Photomicrograph of 7000-cycle track printed
on Eastman 5302 stock, using white light coated lenses
and white light exposure. Print Density 1.2; Print
Gamma 2.5.

FIG. 6. Photomicrograph of 7000-cycle track printed
on Eastman 5302 stock, using ultraviolet coated lenses
and ultraviolet exposure. Print Density 1.2; Print
Gamma 2.5.

eluded that in all cases the best print density was about 1.2. Cross-
modulation tests6 were made which helped to substantiate this
conclusion. In the case of the print made under condition 6, it was
found that the density could be increased to 1.5 without noticeable
loss of quality. The corresponding 35-mm negative densities were
in the commercial range of 1.9 to 2.0.

Figs. 1 through 6 are photomicrographs of 16-mm variable-area,
bilateral, 7000-cycle prints made by optical reduction at a density of

Dec., 1943]

OPTICAL REDUCTION PRINTING

509

1.2 (for Fig. 1, the density is 1.0) under the correspondingly num-
bered conditions of Table I. These photomicrographs show that
when using white light and the original white light optics (Fig. 1)
of the optical reduction printer under study, the print resolution is
improved by coating the lenses (Fig. 2), and still further improved
by the introduction of an ultraviolet filter (Fig. 3), the improvements
being of about the same order of magnitude in each case. The change
to coated lenses designed especially for ultraviolet light (Fig. 4)
increased resolution another step. The photomicrograph of Fig. 5

(7) /i£ASURfO OALWWtfTfR DffLfCTtQ^

UL TRWJOL r r

Q) OUTPUT fKO/f Jfrt/1 ULT/?4M/OL£T />/?/ A/7
fort Si.tr LOSS)

(3)

Ji/r /o xj"
/»y?//vr ^P/VVJ/T-/ /.o

FIG. 7. Reproduced frequency characteristics of an optical reduction
print made on Eastman 5302 stock with white light uncoated lenses and white
light exposure.

shows the resolution obtained when printing on Eastman 5302 stock
with white light using a coated white light optical system, to be lower
than when printing on Eastman 5301 stock with ultraviolet light us-
ing a coated ultraviolet optical system. The photomicrograph of
Fig. 6 shows a print made on Eastman 5302 stock with ultraviolet
light using a coated ultraviolet optical system and represents the
best reduction print quality obtained during the course of the experi-
ments.

The result of coating the lenses was an increase in resolution due to
reduction of stray light, and most notably a reduction of clear area
density from 0.08 to 0.02. At the same time the maximum satis-

510

R. O. DREW AND L. T. SACHTLEBEN [J. s. M. p. E.

factory print density has been raised from about 1.0 to 1.2. As a
result, noise has been reduced and signal level increased.

Table II tabulates in the order of decreasing print quality, the
ratings based on listening tests of the prints made under conditions
of Table I.

TABLE II

Print Quality Rating
1st

2nd
3rd
4th
5th

Condition (See Table I)
6

4
3
5
2

Conclusions drawn from microscopic examination of the prints
were in exact agreement with these ratings.

r t r />•«*

FIG. 8. Reproduced frequency characteristics of an optical reduction print
made on Eastman 5301, with ultraviolet coated lenses and ultraviolet ex-
posure.

The audible quality difference between any two adjacent prints in
the above tabulation was at least a whole order of magnitude and was
in no case a small or doubtful difference.

Figs. 7 through 9 are, respectively, response curves of prints made
from ultraviolet exposed negatives before improvement of the printer
(condition 1), and of the best prints made on the Eastman 5301 and

Dec., 1943]

OPTICAL REDUCTION PRINTING

511

5302 emulsions from ultraviolet negatives using coated ultraviolet
printer lenses and ultraviolet light (conditions 4 and 6). Accom-
panying each curve are curves showing the equalization in the origi-
nal 35-mm negative and the measured response of the 35-mm print
made from it for comparison.

Distortion measurements for several frequencies were made up to
3000 cycles on prints made under conditions 4 and 6 of Table I, and
the total distortion was found to be not greater than 4 per cent.

-IB

/7)

(j)

OJTSLECTIOSS.

FIG. 9. Reproduced frequency characteristics of an optical reduction print
made on Eastman 5302, with ultraviolet coated lenses and ultraviolet ex-
posure.

FILTERING IMPROVEMENTS

Coincident with the experiments directed toward improving the
resolution of the reduction prints, efforts were made to reduce the
frequency variations or wows introduced into them by the printer
itself. Theoretical studies have shown that beyond a certain very
low disturbance frequency, the filtering action of film-moving mecha-
nisms is improved by increasing the frequency of the disturbance.7
This applies to almost all driving systems where filtering of any kind
is employed. Accordingly, tests were made at several increased
printer speeds, up to twice the normal speed or 72 16-mm ft per
minute. It was found that filtering improved with each increase of
speed.

512 R. O. DREW AND L. T. SACHTLEBEN [J. S. M. P. E.

Figs. 10 and 11 are "wowgrams" of reduction prints made at 36 and
72 16-mm ft per minute, respectively. The measured wow was 0.7
per cent at 36 ft per minute, and 0.3 per cent at 72 ft per minute.
These figures express the wow content in terms of peak-to-peak
values; that is, the wow content is the difference between the maxi-
mum and minimum speeds attained during the period covered by the
oscillogram expressed as a per cent of the average speed. The rms
figure for the indicated flutter would be considerably less than half
the above values.

FIG. 10. Oscillogram showing speed variation in print made at 36 ft per min.

FIG. 11. Oscillogram showing speed variation in print made at 72 ft per min.

CONCLUSIONS

Early-type optical reduction printers can be made to give greatly
improved performance by making relatively simple changes in them,
as follows :

(1) Replacement of white light lenses by ultraviolet lenses.

(2) Coating all glass-air surfaces to reduce reflections.

(5) Introduction of an ultraviolet filter in the optical train.
(4) Increase of the printer speed up to 72 16-mm ft per min.

As a result of such changes the quality improvements realized
in the case of the prints made in our tests, were :

(1) Reduction of clear density from 0.08 to 0.02.

(2) Increase of opaque density from 1.0 to 1.2.

Dec., 1943] OPTICAL REDUCTION PRINTING 513

(3) Reduction of loss at 7000 cycles from 18.0 db to 8.4 db.

(4) Limitation of total distortion at frequencies as measured to 4 per cent or
less.

(5) Reduction of speed variations or wow to less than half.

An increase in the printer speed from 36 to 72 ft per minute for the
16-mm film will result in a proportionate increase in the number of
prints produced by the machine.

REFERENCES

1 COLLINS, M. E. : "Optical Reduction Sound Printer," /. Soc. Mot. Pict. Eng.,
XXVII (July, 1936), p. 105.

2 BATSEL, C. N., AND SACHTLEBEN, L. T.: "Some Characteristics of 16-Mm
Sound by Optical Reduction and Re-Recording," /. Soc. Mot. Pict. Eng., XXIV
(Feb., 1935), p. 95.

3 DIMMICK, G. L.: "Improved Resolution in Sound Recording and Printing
by the Use of Ultraviolet Light," /. Soc. Mot. Pict. Eng., XXVII (Aug., 1936), p.
168.

4MAURER, J. A.: "The Present Technical Status of 16-Mm Sound Film,"
J. Soc. Mot. Pict. Eng., XXXIII (Sept., 1939), p. 315.

6 STRONG, J.: "On a Method of Decreasing the Reflection from Non-Metallic
Substances," /. Opt. Soc. Amer., 26 (Jan., 1936), p. 73.

6 BAKER, J. O., AND ROBINSON, D. H.: "Modulated High-Frequency Record-
ing as a Means of Determining Conditions for Optimal Processing," /. Soc. Mot.
Pict. Eng., XXX (Jan., 1938), p. 3.

7 COOK, E. D.: "The Technical Aspects of the High-Fidelity Reproducer,"
/. Soc. Mot. Pict. Eng., XXV (Oct., 1935), p. 289.

CURRENT LITERATURE OF INTEREST TO THE MOTION PICTURE

ENGINEER

The editors present for convenient reference a list of articles dealing with subjects
cognate to motion picture engineering published in a number of selected journals.
Photostatic or microfilm copies of articles in magazines that are available may be
obtained from The Library of Congress, Washington, D. C., or from the New York
Public Library, New York, N. Y., at prevailing rates.

American Cinematographer

24 (Sept., 1943), No. 9

Mitchell 35-Mm Single System Sound Camera
(p. 330)

24 (Oct., 1943), No. 10

The Evolution of Transparency Process Pho-
tography (p. 359)
The New Mitchell Background Projector

(p. 363)

Third-Dimensional Films in Soviet Union
(p. 366)

Educational Screen

22 (Sept., 1943), No. 7
OWI's 16-Mm Motion Picture Program, July,

1942-June, 1943 (p. 233)
Visual Aids in Cleveland Schools (p. 236)
Split-Second Seeing (p. 239)
Motion Pictures — Not for Theaters, Pt. 49
(P. 243)

International Photographer

15 (Sept., 1943), No. 8
A Camera in the Tropics (p. 28)

International Projectionist

18 (July, 1943), No. 7

A Complete Study on the Prevention of Film
Damage (p. 16)

18 (Aug., 1943), No. 8

The Electron Multiplier in Sound Reproduc-
tion (p. 7)

Analysis of a Preview Theater System (p. 10)
Film Distortions: Their Effect Upon Pro-
jection Quality (p. 12)

514

E. J. TIFFANY

F. EDOUART

E. J. TIFFANY

M. KALATOZOV

P. C. REED
M. R. KLEIN
S. R. ELLIS

A. E. KROWS

M. TERRELL

H. B. SELLWOOD

F. J. G. VAN DEN BOSCH
L. CHADBOURNE

E. K. CARVER, R. H. TALBOT,
AND H. A. LOOMIS

CURRENT LITERATURE 515

18 (Sept., 1943), No. 9

Stand-by Features for Sound Systems (p. 7) L. CHADBOURNE
Effect of High-Intensity Arcs Upon 35-Mm
Film Projection (p. 10) E. K. CARVER, R. H. TALBOT,

AND H. A. LOOMIS
Fuses in the Projection Room (p. 16) C. D. WELCH

18 (Oct., 1943), No. 10

Selection and Maintenance of Switches (p. 7) H. B. SELLWOOD
Television Today, I — Electronics Devices

(p. 10) J. FRANK, JR.

Effect of High-Intensity Arcs Upon 35-Mm

Film Projection (p. 12) E. K. CARVER, R. H. TALBOT,

AND H. A. LOOMIS

Motion Picture Herald

152 (Sept. 18, 1943), No. 12
The Light on Your Screen (p. 86) C. E. SHULTZ

SOCIETY ANNOUNCEMENTS
OFFICERS, GOVERNORS, AND MANAGERS, FOR 1944

As a result of the elections held recently, the following is a list of Officers and
Governors of the Society for the term beginning January 1, 1944:

* President: HERBERT GRIFFIN

* Past-President: EMERY HUSE

* Executive Vice-President: LOREN L. RYDER

** Engineering Vice-President: DONALD E. HYNDMAN

* Editorial Vice-President: ARTHUR C. DOWNES
** Financial Vice-President: ARTHUR S. DICKINSON

* Convention Vice-President: WILLIAM C. KUNZMANN

* Secretary: E. ALLAN WILLIFORD

* Treasurer: M. R. BOYER
Governors from the Atlantic Coast Area:

** FRANK E. CARLSON ** EARL I. SPONABLE

* CLYDE R. KEITH * REEVE O. STROCK
** J. A. MAURER * JOSEPH H. SPRAY

Governors from the Pacific Coast Area:

* CHARLES W. HANDLE Y * WILLIAM A. MUELLER
** EDWARD M. HONAN * H. W. REMERSHIED

* HOLLIS W. MOYSE ** WALLACE V. WOLFE

* Term expires December 31. 1944.
'* Term expires December 31, 1945.

510 SOCIETY ANNOUNCEMENTS

Officers and Managers of the Atlantic Coast Section for the term beginning
January 1, 1944, are:

* Chairman: CLYDE R. KEITH

* Past-Chairman: ALFRED N. GOLDSMITH

* Secretary-Treasurer: M. W. PALMER
Managers: ** E. A. BERTRAM

** JAMES FRANK, JR.

* P. C. GOLDMARK

** J. J. HOPKINS

* W. H. OFFENHAUSER, JR.

* H. E. WHITE

Officers and Managers of the Pacific Coast Section for the term beginning Jan-
uary 1, 1944, are:

* Chairman: CHARLES W. HANDLEY

* Past- Chairman: JOHN G. FRAYNE

* Secretary- Treasurer: SIDNEY P. SOLOW
Managers: * M. S. LESHING

** HOLLIS W. MOYSE

* GORDON A. SAWYER
** C. O. SLYFIELD

** W. R. WILKINSON

* WALLACE V. WOLFE

We regret to announce that word has just been received of the death of
Frank F. Renwick, Fellow of the Society, in England on August 14,
1943.

JOURNAL

OF THE SOCIETY OF

MOTION PICTURE ENGINEERS

AUTHOR AND CLASSIFIED
INDEXES

VOLUME XLI
JULY-DECEMBER, 1943

AUTHOR INDEX, VOLUME XLI

JULY TO DECEMBER, 1943

Author
ALNUTT, D. B.

BALDWIN, H. S.

(and CORONITI, S. C.)
BEST, G. M.

BLOOMBERG, D. J.

(and STRANSKY, J.)
BRIGANDI, P. E.

BRIGHT, F. W.
BRUNO, M.

BUENSOD, A. C.

(and WATERFILL, R. W.)

BURRIS-MEYER, H.

CARR, L.

CARVER, E. K.

(and TALBOT, R. H.,
and LOOMIS, H. A.)

CHAMBERS, I. M.
COHEN, E.
COOK, E. D.

CORONITI, S. C.

(and BALDWIN, H. S.)

518

Issue Page

Some Characteristics of Ammonium

Thiosulfate Fixing Baths Oct. 300

Precision Recording Instrument for

Measuring Film Width Nov. 395

Film Conservation Methods at War-
ner Bros. Studios Nov. 459

Film Conservation Methods at Re-
public Studios Nov. 437

Film Conservation Methods at RKO
Studios Nov. 442

Application and Distribution of 16-

Mm Educational Motion Pictures Aug. 190

Maps on Microfilm — Some Factors
Affecting Resolution Nov. 412

Sensible Use of Refrigerants under the
Emergency Now Confronting the
Industry Nov. 426

Recent Developments in Sound Con-
trol for the Legitimate Theater and
the Opera Dec. 494

Sound Control in the Theater Comes

of Age Dec. 500

The Motion Picture in the Service of

the Army Air Forces Oct. 329

Effect of High-Intensity Arcs upon
35-Mm Film Projection July 69

Film Distortions and Their Effect

upon Projection Quality July

Film Conservation Methods at Para-
mount Studios Nov. 449

The Service Films Division of the
Signal Corps Photographic Center Sept. 222

The General Electric Television Film

Projector Oct. 273

Precision Recording Instrument for
Measuring Film Width Nov. 395

INDEX

519

Author

CRABTREE, J. I.
(and EATON, G. T.,
and MUEHLER, L. E.)

DARRACOTT, H. T.

DEMOOS, C.

(and WHITE, D. R.)
DEMoss, G. J.

DREW, R. O.

(and SACHTLEBEN, L. T.)

EATON, G. T.

(and CRABTREE, J. I.,
and MUEHLER, L. E.)

EXTON, W., JR.

FINN, J. D.
GILLETTE, M. E.

GOLDNER, O.

GOODMAN, A.
(and STANKO, E.)

HAINES, A.

HOLSLAG, R. C.
HONAN, E. M.

(and KEITH, C. R.)

HUNGERFORD, O. W.

HYNDMAN, D. E.
JESTER, R.

KALB, W. C.
KEITH, C. R.

(and HONAN, E. M.)

KUYKENDALL, E.

LEASIM, H. W.

LOOMIS, H. A.

(and CARVER, E. K.,
and TALBOT, R. H.)

The Removal of Hypo and Silver
Salts from Photographic Materials
as Affected by the Composition of
the Processing Solutions

Produced by the United States Army
Signal Corps

A Note on the Projection Life of Film

Film Conservation Methods at Uni-
versal Studios

Recent Laboratory Studies of Optical
Reduction Printing

The Removal of Hypos and Silver
Salts from Photographic Materials
as Affected by the Composition of
the Processing Solutions

Developments in the Use of Motion
Pictures by -the Navy

Film Distribution

Some Psychological Factors in Train-
ing Films

Problems in the Production of U. S.
Navy Training Films

RCA Audio Chanalyst— A New In-
strument for the Theater Sound
Engineer

Conservation of Photographic Chemi-
cals

Planning for 16-Mm Production

Recent Developments in Sound-
Tracks

A Compact Production Unit for Spe-
cialized Film

Motion Picture Standards in Wartime

Operations of Army Air Force Combat
Camera Units in the Theaters of
War

Carbon Arc Projection of 16-Mm Film

Recent Developments in Sound-
Tracks

Discussion of Industry Problems

Multiple-Film Scene Selector

Effect of High-Intensity Arcs upon 35-
Mm Film Projection

Film Distortions and Their Effect
upon Projection Quality

Issue Page

July

Sept.
Oct.

Nov.
Dec.

July

Aug.
Sept.

Sept.
Aug.

Dec.

Nov.
Nov.

Oct.
July

Aug.
July

Aug.
Oct.
Sept.

July
July

206
297

434
505

141
251

210
146

467
409

Aug. 127

332
3

136
94

127
336
246

520

INDEX

Author
MILLER, B. F.

MISENER, G. C.

MUEHLER, L. E.

(and CRABTREE, J. I.,
and EATON, G. T.)

NEWELL, D. A.
OFFENHAUSER, W. H., Ji

OUGHTON, C. D.
PRESNEL, R. P.
RAMSEY, R. L.
SACHTLEBEN, L. T.

(and DREW, R. O.)
SHERWOOD, L.

SLYFIELD, C. O.

SMITH, E.
STANKO, E.

(and GOODMAN-, A.)

STARKE, H. A.

STRANSKY, J.

(and BLOOMBERG, D. J.)

TALBOT, R. H.

(and CARVER, E. K.,
and LOOMIS, H. A.)

THOMPSON, L.

TWINING, S. J.

WATERFILL, R. W.
(and BUENSOD, A. C.)

WHITE, D. R.

(and DE Moos, C.)
WOLFF, B. T.

Issue Page

A Motion Picture Arc-Lighting Gen-
erator Filter Nov. 367

Sound Recording at the Signal Corps

Photographic Center Sept. 226

The Removal of Hypo and Silver Salts
from Photographic Materials as
Affected by the Composition of the
Processing Solutions July 9

Film Conservation Methods at Sam-
uel Goldwyn Studios Nov. 455

The 16-Mm Commercial Film Labora-
tory Aug. 157

Notes on the Application of Fine-Grain

Film to 16-Mm Motion Pictures Nov. 374

Resistance of Glass to Thermal Shock Oct. 351

Training Film Production Problems Sept. 215

Field Camera Problems Sept. 239

Recent Laboratory Studies of Optical

Reduction Printing Dec. 505

Editing and Photographic Embel-
lishments as Applied to 16-Mm In-
dustrial and Educatioual Motion
Pictures Dec. 476

Film Conservation Methods at Walt

Disney Productions Nov. 457

Animation in Training Films Sept.. 225

RCA Audio Chanalyst — A New In-
strument for the Theater Sound
Engineer Dec. 467

The Projection of Motion Pictures Aug. 183

Film Conservation Methods at Re-
public Studios Nov. 437

Effect of High-Intensity Arcs upon 35-
Mm Film Projection July 69

Film Distortions and Their Effect

upon Projection Quality July 88

The Practical Side of Direct 16-Mm

Laboratory Work July 101 .

Some Suggested Standards for Direct

16-Mm Production Oct. 340

Film Conservation Methods at Co-
lumbia Studios Nov. 444

Sensible Use of Refrigerants Under
the Emergency Now Confronting
the Industry Nov. 426

A Note on the Projection Life of Film Oct. 297

Film Utilization Sept. 255

CLASSIFIED INDEX, VOLUME XLI

JULY TO DECEMBER, 1943

Air Conditioning

Sensible Use of Refrigerants under the Emergency Now Confronting the In-
dustry, A. C. Buensod and R. W. Waterfill, Nov., p. 426.

Animation

Animation in Training Films, E. Smith, Sept., p. 225.

Apparatus

(See also Instruments)

Multiple-Film Scene Selector, H. W. Leasim, Sept., p. 246.

Arcs

Effect of High-Intensity Arcs upon 35-Mm Film Projection, E. K. Carver,

R. H. Talbot, and H. A. Loomis, July, p. 69.
Carbon Arc Projection of 16-Mm Film, W. C. Kalb, July, p. 94.
A Motion Picture Arc-Lighting Generator Filter, B. F. Miller, Nov., p. 367.

Army, U. S.

Operations of Army Air Force Combat Camera Units in the Theaters of War,

R. Jester, Aug., p. 136.
Produced by the United States Army Signal Corps, H. A. Darracott, Sept., p.

206.

Some Psychological Factors in Training Films, M. E. Gillette, Sept., p. 210.
Training Film Production Problems, R. P. Presnel, Sept., p. 215.
The Service Films Division of the Signal Corps Photographic Center, E. Cohen,

Sept., p. 222.

Animation in Training Films, E. Smith, Sept., p. 225.
Sound Recording at the Signal Corps Photographic Center, G. C. Misener,

Sept., p. 226.

Field Camera Problems, R. L. Ramsey, Sept., p. 239.
Multiple-Film Scene Selector, H. W. Leasim, Sept., p. 246.
Training Film Distribution, J. D. Finn, Sept., p. 251.
Training Film Utilization, B. T. Wolff, Sept., p. 255.

The Motion Picture in the Service of the Army Air Forces, L. Carr, Oct., p. 329.
Maps on Microfilm — Some Factors Affecting Resolution, M. Bruno, Nov., p.

412.

Cameras

Operations of Army Air Force Combat Camera Units in the Theaters of War,

R. Jester, Aug., p. 136.
Field Camera Problems, R. L. Ramsey, Sept., p. 239.

521

522 INDEX [J. S. M. P. E.

Conservation

Conservation of Photographic Chemicals, A. Haines, Nov., p. 409.

Film Conservation Methods at Universal Studios, G. J. DeMoss, Nov., p. 434.

Film Conservation Methods at Republic Studios, D. J. Bloomberg and J.

Stransky, Nov., p. 437.

Film Conservation Methods at RKO Studios, P. E. Brigandi, Nov., p. 442.
Film Conservation Methods at Columbia Studios, S. J. Twining, Nov., p. 444.
Film Conservation Methods at Paramount Studios, I. M. Chambers, Nov., p.

449.
Film Conservation Methods at Samuel Goldwyn Studios, D. A Newell, Nov.,

p. 455.
Film Conservation Methods at Walt Disney Productions, C. O. Slyfield, Nov.,

p. 457.
Film Conservation Methods at Warner Bros. Studios, G. M. Best, Nov., p. 459.

Current Literature
Oct., p. 358; Dec., p. 514.

Distortion

Film Distortions and Their Effect upon Projection Quality, E. K. Carver,
R. H. Talbot, and H. A. Loomis, July, p. 88.

Distribution

Application and Distribution of 16-Mm Educational Motion Pictures, F. W.

Bright, Aug., p. 190.
Training Film Distribution, J. D. Finn, Sept., p. 251.

Editing

Multiple-Film Scene Selector, H. W. Leasim, Sept., p. 246.
Editing and Photographic Embellishments as Applied to 16-Mm Industrial
and Educational Motion Pictures, L. Sherwood, Dec., p. 476.

Educational Motion Pictures

(See also Army, U. S.; Navy, U. S.; Training Films; Sixteen-Mm Motion

Pictures)

Application and Distribution of 16-Mm Educational Motion Pictures, F. W.
Bright, Aug., p. 190.

Film Conservation

(See Conservation)

Film Distortion
(See Distortion)

Film, Fine-Grain

Notes on the Application of Fine-Grain Film to 16-Mm Motion Pictures, W. H.
Offenhauser, Jr., Nov., p. 374.

Film Wear

A Note on the Projection Life of Film, D. R. White and C. deMoos, Oct., p. 297.

Fine-Grain Film

(See Film, Fine- Grain)

Dec., 1943] INDEX 523

Fixing Baths

The Removal of Hypo and Silver Salts from Photographic Materials as Af-
fected by the Composition of the Processing Solutions, J. I. Crabtree, G. T.
Eaton and L. E. Muehler, July, p. 9.

Some Characteristics of Ammonium Thiosulfate Fixing Baths, D. B. Alnutt,
Oct., p. 300.

General

The Association for Scientific Photography, July, p. 120.
Discussion of Industry Problems, E. Kuykendall, Oct., p. 336.

Generators
A Motion Picture Arc-Lighting Generator Filter, B. F. Miller, Nov., p. 367.

Glass

Resistance of Glass to Thermal Shock, C. D. Oughton, Oct., p. 351.

Index

Author: July-December, 1943, Dec., p. 518.
Classified: July- December, 1943, Dec., p. 521.

Instruments

(See also Apparatus)

Precision Recording Instrument for Measuring Film Width, S. C. Coroniti and

H. S. Baldwin, Nov., p. 395.
RCA Audio Chanalyst — A New Instrument for the Theater Sound Engineer,

A. Goodman and E. Stanko, Dec., p. 467.

Intermittent Sprockets

(See Sprockets)

Laboratory Practices

Recent Laboratory Studies of Optical Reduction Printing, R. O. Drew and
L. T. Sachtleben, Dec., p. 505.

Laboratory Practices, 16-Mm

The Practical Side of Direct 16-Mm Laboratory Work, L. Thompson, July, p.

101.
The 16-Mm Commercial Film Laboratory, W. H. Offenhauser, Jr., Aug., p. 157.

Lenses

(See Optics)

Micro Cinematography

Maps on Microfilm — Some Factors Affecting Resolution, M. Bruno, Nov., p.
412.

Navy, U. S.

Developments in the Use of Motion Pictures by the Navy, W. Exton, Jr., Aug.,

p. 141.

Problems in the Production of U. S. Navy Training Films, O. Goldner, Aug., p.
146.

524 INDEX [J. S. M. P. E.

Non-Theatrical Equipment and Film

(See Sixteen-Mm Motion Pictures)

Obituary

Frank H. Richardson, Oct., p. 271.
Frank F. Renwick, Dec., p. 516.

Optical Reduction

(See Printing)

Optics

Resistance of Glass to Thermal Shock, C. D. Oughton, Oct., p. 351.

Printing

Recent Laboratory Studies of Optical Reduction Printing, R. O. Drew and
L. T. Sachtleben, Dec., p. 505.

Processing

The Removal of Hypo and Silver Salts from Photographic Materials as Af

fected by the Composition of the Processing Solutions, J. I. Crabtree, G. T

Eaton, and L. E. Muehler, July, p. 9.
Some Characteristics of Ammonium Thiosulfate Fixing Baths, D. B. Alnutt,

Oct., p. 300.
Notes on the Application of Fine-Grain Film to 16-Mm Motion Pictures, W. H.

Offenhauser, Jr., Nov., p. 374.
Maps on Microfilm — Some Factors Affecting Resolution, M. Bruno, Nov., 412.

Production

Problems in the Production of U. S. Navy Training Films, O. Goldner, Aug., p.

146.

Training Film Production Problems, R. P. Presnel, Sept., p. 215.
A Compact Production Unit for Specialized Film, O. W. Hungerford, Oct., p.

332.
Some Suggested Standards for Direct 16-Mm Production, L. Thompson, Oct.,

p. 340.
Planning for 16-Mm Production, R. C. Holslag, Nov., p. 389.

Projection

Effect of High-Intensity Arcs upon 35-Mm Film Projection, E. K. Carver,

R. H. Talbot, and H. A. Loomis, July, p. 69.
Film Distortions and Their Effect upon Projection Quality, E. K. Carver,

R. H. Talbot, and H. A. Loomis, July, p. 88.
Carbon Arc Projection of 16-Mm Film, W. C. Kalb, July, p. 94.
The Projection of Motion Pictures, H. A. Starke, Aug., p. 183.
A Note on the Projection Life of Film, D. R. White and C. deMoos, Oct.,

p. 297.

Projectors

The General Electric Television Film Projector, E. D. Cook, Oct., p. 273.

Refrigerants

(See Air Conditioning)

Dec., 1943] INDEX 525

Scene Selectors

(See Editing and Apparatus)

Sixteen-Mm Motion Pictures

Carbon Arc Projection of 16-Mm Film, W. C. Kalb, July, p. 94.

The Practical Side of Direct 16-Mm Laboratory Work, L. Thompson, July, p.

101.

The 16-Mm Commercial Film Laboratory, W. H. Offenhauser, Jr., Aug., p. 157.
Application and Distribution of 16-Mm Educational Motion Pictures, F. W.

Bright, Aug., p. 190.
A Compact Production Unit for Specialized Film, O. W. Hungerford, Oct., p.

332.
Some Suggested Standards for Direct 16-Mm Production, L. Thompson, Oct..

p. 340.
Notes on the Application of Fine-Grain Film to 16-Mm Motion Pictures, W. H.

Offenhauser, Jr., Nov., p. 374.

Planning for 16-Mm Production, R. C. Holslag, Nov., p. 389.
Editing and Photographic Embellishments as Applied to 16:Mm Industrial

and Educational Motion Pictures, L. Sherwood, Dec., p. 476.

SMPE Announcements

Fifty-Fourth Semi- Annual Technical Conference: July, p. 119.

Committees and Tentative Program, Aug., p. 195; Sept., p. 263; Oct., p.

360.

Authors and Titles of Papers, Sept., p. 266.
Discontinuance of Mid- West Section, July, p. 119.

Atlantic Coast Section Mailing List, July, p. 119; Aug., p. 199; Sept., p. 269.
Amendments of By-Law IV, Sees. 4 (b) and 5., Sept., p. 269.
Officers and Governors for Term Beginning January 1, 1944, Dec., p. 515.

Sound Control

(See Sound Reproduction)

Sound Effects

(See Sound Reproduction)

Sound Recording

Recent Developments in Sound-Tracks, E. M. Honan and C. R. Keith, Aug.,

p. 127.
Sound Recording at the Signal Corps Photographic Center, G. C. Misener,

Sept., p. 226.

Sound Reproduction

Recent Developments in Sound Control for the Legitimate Theater and the

Opera, H. Burris-Meyer, Dec., p. 494.
Sound Control in the Theater Comes of Age, H. Burris-Meyer, Dec., p. 500.

Sound-Tracks

(See Sound Recording)
Special Effects

Editing and Photographic Embellishments as Applied to 16-Mm Industrial
and Educational Motion Pictures, L. Sherwood, Dec., p. 476.

526 INDEX

Sprockets

A Note on the Projection Life of Film, D. R. White and C. deMoos, Oct., p.
297.

Standards

Motion Picture Standards in Wartime, D. E. Hyndman, July, p. 3.
Some Suggested Standards for Direct 16-Mm Production, L. Thompson, Oct.,
p. 340.

Symposia

Training Film Activities of the U. S. Army, Sept., p. 205.

Film Conservation Methods in Hollywood Studios, Nov., p. 432.

Television

The General Electric Television Film Projector, E. D. Cook, Oct., p. 273.

Training Films

(See also Army, U. S.; Navy, U. S.)

Training Film Activities of the U. S. Army — A Symposium, Sept., p. 205.
A Compact Production Unit for Specialized Film, O. W. Hungerford, Oct., p.
332.

Washing Photographic Materials

The Removal of Hypo and Silver Salts from Photographic Materials as Af-
fected by the Composition of the Processing Solutions, J. I. Crabtree, G. T.
Eaton, and L. E. Muehler, July, p. 9.

MEMBERS OF THE SOCIETY

LOST IN THE SERVICE OF

THEIR COUNTRY

FRANKLIN C. GILBERT

ISRAEL H. TILLES

S. M. P. E. TEST-FILMS

35-Mm. Sound-Film

The recorded frequency range of the voice and music extends to 10,000
cps. ; the constant-amplitude frequencies are in 15 steps from 50 cps. to
10,000 cps. Price $37.50 each.

35-Mm. Visual Film

16-Mm. Sound-Film

The recorded frequency range of the voice and music extends to 6000
cps.; the constant-amplitude frequencies are in 11 steps from 50 cps. to
6000 cps. Price $25.00 each.

16-Mm. Visual Film

An optical reduction of the 35-mm. visual test-film, identical as to
contents and approximately 225 feet long. Price $25.00 each.

SOCIETY OF MOTION PICTURE ENGINEERS

HOTEL PENNSYLVANIA

NEW YORK, N. Y.

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